A senior U.S. commander said Wednesday that recent attacks in Iraq are the work of groups seeking to sabotage -- or gain leverage in -- a future independent Iraqi government that is due to take power by July.

Maj. Gen. Raymond Odierno, commander of the Army's 4th Infantry Division (search), also predicted that coalition forces would be able to crush the insurgency within a year, despite continued American losses since the Dec. 13 capture of Saddam Hussein (search).

"There are ethnic issues. People are now positioning themselves to see what their role is in the next government, and they are doing it by force," Odierno said after a tour of this city, Saddam's hometown. "They are trying to disrupt the way things are going so they can get a little advantage."

On Wednesday, an Iraqi insurgent group claimed responsibility for twin bombings that killed 109 people at the offices of two Kurdish political parties on Sunday. The "Jaish Ansar al-Sunna" said it targeted the "dens of the devils" because of the parties' ties to the United States. The claim could not be independently confirmed.

The U.S.-led Coalition Provisional Authority (search) plans to hand over sovereignty to a provisional Iraqi government on June 30. The United Nations soon will dispatch a team to Iraq to resolve differences between the Americans and the Shiite Muslim clergy over how to choose the new Iraqi leadership.

"We have six to 12 months left of this insurgency," Odierno said. "I think constant pressure will bring it down."

So far, 528 U.S. service members have died since the Iraq war began March 20, including 368 by hostile fire. Forty-five soldiers died in January and three more in the first three days of February. The January toll was five more than in December, despite hopes that Saddam's capture would weaken the insurgency and slow the killings from roadside bombs and other attacks.

In another fatality, a Spanish military adviser who fell into a coma after being seriously wounded in a shootout last month died Wednesday, the Spanish Defense Ministry said. The shootout occured in the town of Hamsa, about 25 miles south of Diwaniyah, where the Spanish troops are based.

Civil Guard commander Gonzalo Perez Garcia's death brought to 11 the number of Spaniards that have been killed in Iraq since August.

Odierno, the U.S. major general who is in charge of security over a large swath of north-central Iraq, did not elaborate on how insurgent attacks were aimed at gaining advantage before the power transfer. He also did not offer specific examples of such attacks.

However, a recent series of major attacks were clearly aimed at Iraqi targets, raising fears that insurgents were going after those who would play major political and security roles in a future Iraqi government.

On Sunday, two homicide bombers struck simultaneously at the offices of two Kurdish political parties in Irbil, killing 109 people -- the biggest confirmed death toll in any insurgent attack since the start of the Iraq conflict last March.

Among the dead were many key leaders of the Kurdistan Democratic Party and the Patriotic Union of Kurdistan, the two U.S.-backed parties that run the Kurdish autonomous region of northern Iraq.

On Saturday, a car bomb killed nine people and wounded 45 at a police station in the northern metropolis of Mosul. A Jan. 24 truck bomb that killed two Iraqis and wounded about 40 other people -- including seven American soldiers -- may have been aimed at disrupting a municipal council meeting, officials said.

Other attacks appear to have been targeted against different religious groups. Last month, a bomb exploded in front of a Shiite Muslim mosque in the predominantly Sunni city of Baqouba, killing five people and wounding dozens of others.

Pamphlets allegedly signed by 12 insurgent groups appeared this week in the Sunni Triangle cities of Ramadi and Fallujah west of the capital, warning Iraqis against cooperating with Americans and their occupation allies. The pamphlets said Iraqis who did not cooperate with the Americans would form new city councils to run the municipalities.

U.S. commanders have said they plan to shift security responsibility to newly trained Iraqi forces, accelerating those moves in coming months when the U.S. military replaces units that have been in the country for months with fresh troops.

Elsewhere, police arrested nine suspected guerrillas and seized two rockets set up to fire at a U.S. base south of Kirkuk, police chief Torhan Abdul-Rahman Yousif said Wednesday.

U.S. troops, meanwhile, arrested a relative of Izzat Ibrahim al-Douri (search), and believe he may help in the hunt for the most senior former regime figure still at large, a U.S. officer said Wednesday.

Al-Douri was the vice chairman of the Baath Party's Revolutionary Command Council and a longtime confidant of Saddam. He is No. 6 on the wanted list and U.S. forces have offered a $10 million bounty for his arrest.