Bush administration officials are calling on Senator John Kerry to name the foreign leaders who he says want him to defeat the president in the November election.
Last week, Massachusetts Senator John Kerry, the presumptive Democratic presidential nominee, told supporters in Florida that some foreign leaders had told him privately that they want him to defeat Mr. Bush.
On Monday, presidential spokesman Scott McClellan told reporters at the White House that it was time for Senator Kerry to be "straightforward" and identify the leaders in question. Otherwise, Mr. McClellan said, "he is making it up to attack the president."
The McClellan comments followed a response Sunday by Secretary of State Colin Powell. He was asked about Senator Kerry's comments on Fox News Sunday.
"I don't know what foreign leaders Senator Kerry is talking about. It is an easy charge, an easy assertion to make," he said. "But if he feels it is that important an assertion to make, he ought to list some names. And if he can't list names, then perhaps he should find something else to talk about."
Senator Kerry was pressed to defend his remarks at a rally Sunday in Pennsylvania when a Bush supporter got up and challenged him to identify the foreign leaders in question.
"I haven't met with any foreign leaders for any overthrow purposes. I haven't said that," he said. "What I said was that I have heard from people who are leaders elsewhere in the world who don't appreciate the Bush administration approach and would love to see it change in the leadership of the United States."
Senator Kerry says he will not name the foreign leaders out of concern for their privacy.
The controversy is but the latest example of the increasingly combative nature of the campaign in advance of an election more than seven months away.