Iraqi police say at least 80 people were killed Monday when two suicide car bombers struck in the northern city of Kirkuk.
In the first attack a car bomber struck the local office of the Patriotic Union of Kurdistan, the party of Iraqi President Jalal Talabani.
About 20 minutes later, a second attack nearby hit a crowded market frequented by Kurds. More than 100 people were wounded in the two attacks.
In the capital, U.S. forces say thousands of troops launched a new offensive in southern Baghdad Monday with the aim of cutting off the flow of weapons and militants into the capital.
The new sweep, called Marne Avalanche, is the latest around Baghdad as part of the so-called "surge" of 28,000 new American troops.
In other violence Monday, five Iraqi soldiers were killed by a roadside bomb in northeast Baghdad.
Also, mortar shells hit a residential area in southern Baghdad, killing at least two civilians and wounding six.
On Sunday, U.S. National Security Advisor Stephen Hadley said the White House has rejected a proposal by two influential Republican Party senators to reduce the number of U.S. forces in Iraq.
During appearances on Sunday television programs, Hadley said President Bush will wait for September's planned military review of the war. He also said the United States will have to be engaged in Iraq for a "considerable period of time."
A proposal by Senators John Warner and Richard Lugar would reduce U.S. involvement in policing sectarian violence. Instead, U.S. forces would focus on fighting foreign terrorists and preserving Iraq's territorial integrity.
Some information for this report was provided by AFP, AP and Reuters.