( AP ) - Nearly 4,000 U.S. soldiers have arrived in Baghdad as a crackdown aimed at quelling the sectarian violence enters its 12th week. Meanwhile, bombings and shootings killed 10 people Wednesday, including three Sunni brothers who were shot to death in Baghdad.
The security efforts come as President Bush is engaged in a fierce debate with the Democratic-led Congress over the war in Iraq. Bush vetoed legislation to pull U.S. troops out of Iraq Tuesday night in a historic showdown with Congress over whether the unpopular and costly war should end or escalate.
Meanwhile, an international conference on Iraq begins Thursday in the Egyptian Red Sea resort of Sharm el-Sheik at which the U.S. administration is expected to press hard for countries to forgive billions of dollars in Iraqi debt to help the Shiite-led government as it tries to rein in the violence.
Gunmen killed the three Sunni brothers about 3 a.m. and set the house on fire in a religiously mixed neighborhood of Rusala in western Baghdad, police said.
A bomb exploded near a house belonging to a displaced Shiite family in Hillah, about 60 miles south of Baghdad, killing a man and wounding his wife, according to provincial police.
Elsewhere, a roadside bomb struck a minibus in Mahmoudiya, 20 miles south of the capital, killing three people and wounding four, police said. The bus was carrying passengers to Baghdad.
Two mortar rounds also fell on a residential area elsewhere in the volatile city, killing three people and wounding 13, police said.
Iraq and U.S. officials have been cautiously optimistic about the joint operation in Baghdad that began on Feb. 14 but stressed it was still in its early stages as all the American troops being sent as reinforcements were not expected to be in place until early June.
The U.S. military said Wednesday that the fourth of five brigades being sent to help Iraqi security forces as part of the crackdown had arrived this week.
The 4th Brigade, 2nd Stryker Brigade Combat Team from Fort Lewis, Wash., which includes about 3,700 soldiers, will be deployed in the Baghdad area and in northern Iraq, the military said. Officials want the rest in place by June, for a total of 160,000.
On Tuesday, Bush rejected legislation pushed by Democratic leaders that would require the first U.S. combat troops to be withdrawn by Oct. 1 with a goal of a complete pullout six months later. It was only the second veto of his presidency.
"This is a prescription for chaos and confusion and we must not impose it on our troops," Bush said in a nationally broadcast statement from the White House. He said the bill would "mandate a rigid and artificial deadline" for troop pullouts, and "it makes no sense to tell the enemy when you plan to start withdrawing."
Democrats accused Bush of ignoring Americans' desire to stop the war, which has claimed the lives of more than 3,350 members of the military.
Ismail Qassim, a 41-year-old Shiite electricity ministry employee in Baghdad, welcomed the move.
"In spite of all the problems Iraq is facing because of the American presence, there is some need for them at least for one more year because of the sectarian strife in Iraq and corruption in the security services," he said.
But Sameer Hussein, a 22-year-old Sunni college student in Baghdad, said he wanted the U.S. forces to withdraw but didn't think they ever would.
"Even if they will withdraw they will leave permanent military bases in Iraq and that is something Iraqi people will reject," he said.
A senior Interior Ministry official, meanwhile, said officials were trying to gain custody of Abu Ayyub al-Masri's body amid widespread skepticism over claims that the leader of al-Qaida in Iraq had been killed.
Maj. Gen. Hussein Kamal declined to comment further, but a police official in Anbar province said al-Masri died when his explosives belt detonated during fighting but security forces could not retrieve the body because it was in a part of the desert controlled by the terror group. U.S. authorities urged caution about the reports, saying they had not been confirmed and warning that even if the claim were true, the death of the shadowy Egyptian militant likely would not spell the end of the terror movement in Iraq.
Separately, an Iraqi military spokesman said most of the operations as part of the crackdown were taking place in volatile areas outside Baghdad, including the Sunni cities of Mahmoudiyah and Madain.
Brig. Gen. Qassim al-Moussawi, the spokesman for matters related to the security crackdown, said insurgent operations had dropped significantly in Baghdad as the groups had fled to other areas.
"Next week will witness more military operations in both halves of Baghdad," he said, referring to the two sides of the Tigris River that divides Baghdad. "Almost all our military operations are now taking place on Baghdad's outskirts."
He added that 52 civilians were killed and 101 were wounded in explosions over the past week, while four terror suspects were killed and 158 others detained. He also said security forces had dismantled 146 roadside bombs and 27 car bombs, and they found 50 containers of nitric acid and other explosive material.