The White House has hit back at reports that US president Barack Obama fears Mitt Romney may pick CIA chief David Petraeus as his running mate.
The Republican candidate is expected to announce his running mate this month, and US media is reporting that he is pursuing General Petraeus to run for vice-president.
Fuelling the speculation, the online Drudge Report site ran a story in which it quoted an "insider" as saying that Mr Obama had whispered to a supporter this week that he thought Romney wanted to select the popular retired general.
"The president wasn't joking," the site quoted the "insider" as saying.
General Petraeus implemented a troop surge in Iraq in 2007 that is credited with turning the tide against the bloody sectarian insurgency.
But Mr Obama's spokesman Jay Carney says reports that the president fears the decorated war hero could jump ship are ridiculous.
"Be mindful of your sources," Mr Carney told a reporter who queried him on the Drudge article.
"I can say with absolute confidence that such an assertion has never been uttered by the president.
"Petraeus was an excellent general and is currently serving very well at the Central Intelligence Agency."