Finally! But she ain't out of the woods yet...
Clinton takes key primary polls
Mrs Clinton insists she can go all the way to the White House
Hillary Clinton has revived her campaign for the US presidency with projected primary election wins in three states.
US media say she has taken the Democratic primary polls in Texas, Ohio and Rhode Island. The results of caucus meetings in Texas are not yet known.
Rival Democrat Barack Obama took the primary in the state of Vermont.
Meanwhile, John McCain has won the Republican nomination with projected wins in all the four states.
His closest rival, Mike Huckabee, has dropped out of the race and pledged to support Mr McCain's candidacy.
Mr McCain's victories take him over the threshold of 1,191 delegates needed to claim the nomination at the party's national convention in September.
Both Democratic candidates called Mr McCain to congratulate him on clinching the Republican candidacy.
Speaking to jubilant crowds in Columbus, Ohio, Mrs Clinton said she was determined to stay in the race and looked forward to continuing the debate with Mr Obama "in the weeks ahead".
"For everyone here in Ohio and across America who has ever been counted out but refused to be knocked out, for everyone who has stumbled but stood right back up, and for everyone who works hard and never gives up, this one is for you," she said.
Mrs Clinton also pointed to Ohio's status as a state which had picked the winning presidential nominee in every contest in recent history.
"You know what they say - as Ohio goes, so goes the nation. Well, this nation's coming back and so is this campaign," she said.
"The people of Ohio have said it loudly and clearly: we're going on, we're going strong and we're going all the way."
According to the Associated Press, she still trails Mr Obama with 1,376 delegates to his 1,466, with some delegates in Ohio and Texas yet to be allocated.
However, the BBC's Vincent Dowd in Washington says that while Tuesday's voting has not made much difference to the senators' relative standing in terms of delegates, the psychological boost for the Clinton camp is huge.
Mr McCain's path to the Republican nomination represents a remarkable comeback after his campaign was all but written off following setbacks last summer.
Speaking to supporters in Dallas, Texas, he said the most important part of the campaign now lay ahead, in which he must "make a respectful, determined and convincing case to the American people" to pick him over the Democratic candidate in November.
Mr McCain went on to outline the challenges facing the nation, including the war in Iraq and the fight against al-Qaeda and the Taleban.
He also pledged a campaign that avoided "false promises", and appealed for voters to "stand up and fight for America, for her strength, her ideals and her future".
He will go to the White House on Wednesday for lunch with George W Bush, when he is expected to receive the president's endorsement.
Conceding the race at a rally in Irving, Texas, Mr Huckabee said: "It's now important that we turn our attention not to what could have been or what we wanted to have been but what now must be, and that is a united party."
For the Democrats, a total of 370 delegates to the nominating party convention in August were at stake in Tuesday's four races, to be divided proportionally.
The results from the Texas caucuses - meetings at which voters gather to indicate their support for their chosen candidate - have not been finalised, so the final delegate count is not yet known.
Hillary Clinton
16 states, 1,376 delegates
Arizona, Arkansas, California, Florida, Massachusetts, Michigan, Nevada, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Rhode Island, Tennessee, Texas
Barack Obama
24 states, 1,466 delegates
Alabama, Alaska, Colorado, Connecticut, Delaware, Georgia, Hawaii, Idaho, Illinois, Iowa, Kansas, Louisiana, Maine, Maryland, Minnesota, Missouri, Nebraska, North Dakota, South Carolina, Utah, Vermont, Virginia, Washington state, Wisconsin
2,025 delegates needed for nomination. Source AP (includes all kinds of delegates)
Mike Huckabee
8 states, 261 delegates
Campaign ended
Alabama, Arkansas, Georgia, Iowa, Tennessee, West Virginia, Kansas, Louisiana
John McCain
20 states, 1,215 delegates
Arizona, California, Connecticut, Delaware, Florida, Illinois, Maryland, Missouri, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Rhode Island, South Carolina, Texas, Vermont, Virginia, Washington state, Wisconsin
Mitt Romney
11 states, 255 delegates
Campaign suspended
Alaska, Colorado, Maine, Massachusetts, Michigan, Minnesota, Montana, Nevada, North Dakota, Wyoming, Utah
1,191 delegates needed for nomination. Source: AP (includes all kinds of delegates)
Between the nationwide Super Tuesday contests on 5 February and the 4 March polls, Mr Obama won 11 contests in succession, giving him a lead over Mrs Clinton in the delegate count and apparently unstoppable momentum.
Addressing supporters in San Antonio, Texas, Mr Obama congratulated Mrs Clinton on running a "hard-fought race" but pointed out that he still held the advantage.
"No matter what happens tonight, we have nearly the same delegate lead as we did this morning, and we are on our way to winning this nomination," he said.
Mr Obama also used his speech to attack Mr McCain's policies on Iraq, warning that he would lead the country on the same course as Mr Bush had followed.
The economy was the most important issue for Democratic voters in all four states, especially Ohio, according to exit polls. The Iraq war was a close second in Vermont.
Those polls also suggested Mrs Clinton was doing well among white, blue-collar and older voters in Ohio, which may indicate she has halted Mr Obama's advance into those groups, her core base until recent contests.
-BBC News
Theres still a long way to go for her. Although she has victory, its not a landslide one which she needs. This contest WILL go on. And it ain't over till the fat lady sings.
Mrs Clinton insists she can go all the way to the White House
Hillary Clinton has revived her campaign for the US presidency with projected primary election wins in three states.
US media say she has taken the Democratic primary polls in Texas, Ohio and Rhode Island. The results of caucus meetings in Texas are not yet known.
Rival Democrat Barack Obama took the primary in the state of Vermont.
Meanwhile, John McCain has won the Republican nomination with projected wins in all the four states.
His closest rival, Mike Huckabee, has dropped out of the race and pledged to support Mr McCain's candidacy.
Mr McCain's victories take him over the threshold of 1,191 delegates needed to claim the nomination at the party's national convention in September.
Both Democratic candidates called Mr McCain to congratulate him on clinching the Republican candidacy.
Speaking to jubilant crowds in Columbus, Ohio, Mrs Clinton said she was determined to stay in the race and looked forward to continuing the debate with Mr Obama "in the weeks ahead".
"For everyone here in Ohio and across America who has ever been counted out but refused to be knocked out, for everyone who has stumbled but stood right back up, and for everyone who works hard and never gives up, this one is for you," she said.
Mrs Clinton also pointed to Ohio's status as a state which had picked the winning presidential nominee in every contest in recent history.
"You know what they say - as Ohio goes, so goes the nation. Well, this nation's coming back and so is this campaign," she said.
"The people of Ohio have said it loudly and clearly: we're going on, we're going strong and we're going all the way."
According to the Associated Press, she still trails Mr Obama with 1,376 delegates to his 1,466, with some delegates in Ohio and Texas yet to be allocated.
However, the BBC's Vincent Dowd in Washington says that while Tuesday's voting has not made much difference to the senators' relative standing in terms of delegates, the psychological boost for the Clinton camp is huge.
Mr McCain's path to the Republican nomination represents a remarkable comeback after his campaign was all but written off following setbacks last summer.
Speaking to supporters in Dallas, Texas, he said the most important part of the campaign now lay ahead, in which he must "make a respectful, determined and convincing case to the American people" to pick him over the Democratic candidate in November.
Mr McCain went on to outline the challenges facing the nation, including the war in Iraq and the fight against al-Qaeda and the Taleban.
He also pledged a campaign that avoided "false promises", and appealed for voters to "stand up and fight for America, for her strength, her ideals and her future".
He will go to the White House on Wednesday for lunch with George W Bush, when he is expected to receive the president's endorsement.
Conceding the race at a rally in Irving, Texas, Mr Huckabee said: "It's now important that we turn our attention not to what could have been or what we wanted to have been but what now must be, and that is a united party."
For the Democrats, a total of 370 delegates to the nominating party convention in August were at stake in Tuesday's four races, to be divided proportionally.
The results from the Texas caucuses - meetings at which voters gather to indicate their support for their chosen candidate - have not been finalised, so the final delegate count is not yet known.
Hillary Clinton
16 states, 1,376 delegates
Arizona, Arkansas, California, Florida, Massachusetts, Michigan, Nevada, New Hampshire, New Jersey, New Mexico, New York, Ohio, Oklahoma, Rhode Island, Tennessee, Texas
Barack Obama
24 states, 1,466 delegates
Alabama, Alaska, Colorado, Connecticut, Delaware, Georgia, Hawaii, Idaho, Illinois, Iowa, Kansas, Louisiana, Maine, Maryland, Minnesota, Missouri, Nebraska, North Dakota, South Carolina, Utah, Vermont, Virginia, Washington state, Wisconsin
2,025 delegates needed for nomination. Source AP (includes all kinds of delegates)
Mike Huckabee
8 states, 261 delegates
Campaign ended
Alabama, Arkansas, Georgia, Iowa, Tennessee, West Virginia, Kansas, Louisiana
John McCain
20 states, 1,215 delegates
Arizona, California, Connecticut, Delaware, Florida, Illinois, Maryland, Missouri, New Hampshire, New Jersey, New York, Ohio, Oklahoma, Rhode Island, South Carolina, Texas, Vermont, Virginia, Washington state, Wisconsin
Mitt Romney
11 states, 255 delegates
Campaign suspended
Alaska, Colorado, Maine, Massachusetts, Michigan, Minnesota, Montana, Nevada, North Dakota, Wyoming, Utah
1,191 delegates needed for nomination. Source: AP (includes all kinds of delegates)
Between the nationwide Super Tuesday contests on 5 February and the 4 March polls, Mr Obama won 11 contests in succession, giving him a lead over Mrs Clinton in the delegate count and apparently unstoppable momentum.
Addressing supporters in San Antonio, Texas, Mr Obama congratulated Mrs Clinton on running a "hard-fought race" but pointed out that he still held the advantage.
"No matter what happens tonight, we have nearly the same delegate lead as we did this morning, and we are on our way to winning this nomination," he said.
Mr Obama also used his speech to attack Mr McCain's policies on Iraq, warning that he would lead the country on the same course as Mr Bush had followed.
The economy was the most important issue for Democratic voters in all four states, especially Ohio, according to exit polls. The Iraq war was a close second in Vermont.
Those polls also suggested Mrs Clinton was doing well among white, blue-collar and older voters in Ohio, which may indicate she has halted Mr Obama's advance into those groups, her core base until recent contests.
-BBC News
Theres still a long way to go for her. Although she has victory, its not a landslide one which she needs. This contest WILL go on. And it ain't over till the fat lady sings.