The White House has blamed insurgents seeking to derail Iraqi elections for a deadly attack at a US base in northern Iraq, which presented a fresh challenge for US President George W Bush.
White House Spokesman Scott McClellan said the insurgents would be defeated and a free and peaceful Iraq will emerge.
Meanwhile, as a new poll showed a majority of Americans now believe the Iraq war was not worth fighting, President Bush was described as mourning the loss of life in the latest attack and praying for the families of those who were killed.
The rocket and mortar attack in Mosul killed at least 24 people and wounded around 60 others. 18 US soldiers are reported to be among those killed.
It took place as Mr Bush prepared to visit families of wounded soldiers at a housing facility at Walter Reed Army Medical Centre near Washington.
Blair holds Baghdad talks
In a separate development, British Prime Minister Tony Blair held talks with Iraqi leaders in Baghdad during his first trip to the city.
He was briefed on preparations for the national election, which is scheduled for next month but is threatened by a deadly campaign of insurgent violence.
Mr Blair also met the American commander of the multi-national force, General George Casey and his British deputy, General John Kiszely at the US embassy.
At a news conference, Mr Blair said he hoped the elections would take place as scheduled and he praised Iraqi election officials as heroes, who were risking their lives.
His visit had not been announced because of a news blackout requested by Downing Street.
