The White House has called on Democrat presidential candidate Senator John Kerry to name the foreign leaders who he says want him to defeat President George W. Bush.
The Republican White House was trying to capitalise on Mr Kerry's recent comment that he had spoken to foreign leaders who wanted him to beat President Bush in the November election and change the course of US foreign policy.
Mr Bush was at odds with leaders of France, Germany, Russia, Canada and other nations during the Iraq conflict because they refused to go to war without UN sanction. His coalition in favour of war included Spain, whose pro-US government was defeated in elections on Sunday.
"If Senator Kerry is going to say he has support from foreign leaders, then he needs to be straightforward with the American people and say who it is that he has spoken with and who it is that supports him," White House spokesman Mr Scott McClellan told reporters.
If not, the spokesman added, "Then the only alternative is that he is making it up to attack the president of the United States."
Mr Kerry refused on Sunday to name names. "No leader would obviously share a conversation if I started listing them," he said.
Civil rights activist the Rev Al Sharpton - the only black candidate in the Democrat presidential nomination race - ended his bid for the White House and endorsed Mr Kerry.