US President George W. Bush has warned that the war in Iraq will be won "no matter how long it takes".
Mr Bush refused to be drawn into setting a deadline for an end to the war.
"This isn't a matter of timetable, it's a matter of victory," he said after a war council with his main ally, British Prime Minister Tony Blair.
"The Iraqi people have got to know . . . that they will be liberated and [Iraqi president] Saddam Hussein will be removed, no matter how long it takes," Mr Bush said.
US and British forces are facing stiffer Iraqi resistance than expected across southern Iraq and harried by irregular forces striking drawn-out supply lines.
As the US-led assault on Iraq went into its ninth day, CNN reported that US B-52 bombers for the first time dropped a 4,500-pound "bunker-busting" bomb on the capital. A Pentagon spokesman would not confirm the report.
Overnight fires raged in central Baghdad as missiles targeted key communications, command and control positions, knocking out many telephone lines.