In quotes: US primaries

Politicians react to the results of key primaries in Texas, Ohio, Rhode Island and Vermont as Republican and Democratic candidates vie for their parties' nominations.

JOHN MCCAIN, REPUBLICAN CANDIDATE

The contest begins tonight. It will have its ups and downs. But we will fight every minute of every day to make certain we have a government that is as capable, wise, brave and decent as the great people we serve.

That is our responsibility and I will not let you down.

BARACK OBAMA, DEMOCRATIC CANDIDATE

We have nearly the same delegate lead as we did this morning and we are on our way to winning this nomination.

HILLARY CLINTON, DEMOCRATIC CANDIDATE

You know what they say. As Ohio goes, so goes the nation. Well, this nation's coming back, and so is this campaign.

We're going on, we're going strong, and we're going all the way.

JOHN GLENN, FORMER OHIO SENATOR

Ohio, more than any state in the union, represents the whole United States.

CHARLES GONZALES, TEXAS CONGRESSMAN, OBAMA SUPPORTER

You better start figuring out where the Democrats are going to bring a lot more people over from the other side - Republicans and independents - but also that Barack Obama will bring new voters.

JAMES RUBIN, FORMER ASSISTANT SECRETARY OF STATE

Hillary Clinton has shown that she has the ability to get up off the floor - 11 straight defeats - and win what I think everybody recognises to be a crucial state in American politics. No president has ever been elected who hasn't won their primary in Ohio in recent memory.