The United States last night dismissed a conditional truce offered in a tape attributed to Osama bin Laden.
Vice-president Dick Cheney said the offer from the al-Qaeda leader appeared to be a ploy but that it was too early to draw conclusions.
The audiotape, aired by Arab television station al-Jazeera, also warned al-Qaeda was preparing new attacks inside the United States.
"Clearly the al-Qaeda leaders and other terrorists are on the run, they're under a lot of pressure. We do not negotiate with terrorists, we put them out of business," White House spokesman Scott McClellan told reporters.
"The terrorists started this war and the president made it clear that we will end it at a time and place of our choosing. We continue to pursue all those who seek to do harm to the American people," he said.
A CIA official said US intelligence analysts believed the voice on the tape - the first from bin Laden since 2004 - belonged to the al-Qaeda leader.
In it, bin Laden warned of new attacks inside the United States. But he said al Qaeda was willing to "respond" to US public opinion in favour of withdrawing troops from Iraq. Bin Laden did not specify conditions for the truce but indicated that it was linked to US troops quitting Iraq.