Three U.S. presidential candidates displayed their diplomacy on Thursday as they held the one-on-one meeting separately with the visiting British Prime Minister, Gordon Brown.

Britain's Prime Minister Gordon Brown (L) and U.S. Democratic presidential candidate Barack Obama shake hands before meeting at the British ambassador's residence in Washington, April 17, 2008.

Brown, who is on his second visit to the United States since he came in office in June, granted a 45-minute meeting to each of the three White House hopefuls.

Illinois Senator Barack Obama, the only one among the three who has never met Brown in person before, was prepared to discuss how to develop the U.S.-U.K. relations and revive the trans-Atlantic alliance, his campaign said.

His rival, New York Senator Hillary Rodham Clinton, brought out a wide range of issues to Brown, including the Iraq and Afghanistan wars as well as the global warming issue, according to a CNN report.

U.S. Democratic presidential candidate Senator Hillary Clinton (D-NY) walks with Britain's Prime Minister Gordon Brown at the British ambassador's residence in Washington, April 17, 2008.

John McCain, the presumptive Republican presidential candidate who just met Brown when visiting London last month, was heard talking about the race for the White House and seen taking pictures with Brown.

The diplomatic issues have dominated the presidential nomination races, especially those about the Iraq and Afghanistan wars, with all of the three candidates proposing different plans on the U.S. military presence in Iraq.

Obama, who is still in his first four-year term in the Senate, was mocked "naive" for saying that he would meet with Iranian President Mahmoud Ahmadinejad to break the standoff between the two countries caused by the Iran nuclear issue.

(Xinhua News Agency April 18, 2008)