The US military has said it is reviewing strategy in Baghdad after failing to halt spiralling violence.
The battle for control of Baghdad, which US officials say will decide Iraq's future, and a spate of attacks across Iraq yesterday that killed at least 38 people piled pressure on President Bush before the November mid-term election.
In Washington, a senior administration official said the latest Baghdad security strategy had not achieved its goal and that the top US commander in Iraq, Gen George Casey, was expected to present a revised plan within weeks.
The US military will be looking at the "adequacy" of Iraqi forces deployed in Baghdad, whether to change the balance of Iraqi police and soldiers in the city, and the role of US troops there, the official said.
Mr Bush, whose Republicans are battling to retain control of Congress, said he saw a possible parallel in the rise in violence in Iraq and the 1968 communist Tet offensive, which triggered a drop in Americans' support for the Vietnam war.
Asked in an ABC television interview whether he agreed the violence in Iraq was the "jihadist equivalent of the Tet offensive," Mr Bush said: "(It) could be right. There's certainly a stepped up level of violence and we're heading into an election."
Mr Bush said al-Qaeda was very active in Iraq and trying to foment sectarian violence as well as kill US troops.
Later, at a Republican fundraising event, he said: "There is one thing we will not do. We will not pull out our troops from Iraq before the terrorists are defeated."