Mr Bush will go to the huge Fort Bragg army base in North Carolina to give the speech marking the first anniversary of the transfer of civilian authority from United States to an Iraqi government.

He will also meet privately with parents of some of the more than 1,700 US military who have died in Iraq since the US-led invasion in March, 2003.

White House spokesman Scott McClellan said “significant progress” had been made since the handover, most notably the landmark January elections and the installation of a transitional government under Prime Minister Ibrahim al-Jaafari, who last week met with Bush at the White House.

Nevertheless, the US public is increasingly questioning the need to keep 135,000 US troops in Iraq.

According to survey published last week, 59 percent of Americans want a partial or total pullout of US forces from Iraq, where daily insurgent attacks are taking a mounting toll.

US Vice President Dick Cheney recently said that the insurgency is currently in its “last throes” but US military officials have been less sanguine.

And Defense Secretary Donald Rumsfeld told US television on Sunday that the insurgency could go on for “years”.

“Insurgencies tend to go on five, six, eight, 10, 12 years,” he told Fox television.

Having used Iraq’s alleged weapons of mass destruction to justify the war, Bush has now had to change tack following the failure to find them.

He now justifies the US presence in Iraq as part of the US “war on terror” and its efforts to spread democracy in the Middle East.

Looking ahead to the speech, the White House spokesman said: “I think one thing the president will do is talk about the nature of the enemy that we face in Iraq. These are terrorists that have no regard for human life. They are a determined and ruthless enemy that has made Iraq a central front in the war on terrorism.”