President George W. Bush's attempt to persuade a sceptical US public of the need to keep troops in Iraq has exposed growing tensions among Democrats over the stance they should take on the war.

Nancy Pelosi, the Democratic leader in the House of Representatives, responded to Mr Bush's explanation of his Iraq strategy by endorsing a call for the prompt withdrawal of US troops. But Steny Hoyer, her second-in-command, disagreed. "I believe a precipitous withdrawal of American forces in Iraq could lead to disaster, spawning a civil war, fostering a haven for terrorists and damaging our nation's security and credibility," he said on Thursday.