BAGHDAD, Iraq (AP) - U.S. reinforcements sent to Baghdad to help quell sectarian violence and clamp down on other attacks took up positions in a restive neighborhood Saturday, while two bombs at a market northeast of the city wounded eight people.

The 3,700 soldiers of the Army's 172nd Stryker Brigade moved in from the northern city of Mosul to bolster U.S. and Iraqi security forces already in the city.

Several Stryker armored fighting vehicles were seen Saturday in Baghdad's mostly Sunni neighborhood of Ghazaliyah in the western part. Iraqi police used loudspeakers to encourage residents to go about their business and reopen shops because the troops were there to protect them.

Dozens of people are killed almost every day in Iraq, mostly in sectarian violence between Shiite and Sunni extremists that has escalated since a Shiite shrine was bombed Feb. 22 in Samarra.

Baghdad has been the focus of much of the sectarian bloodshed, along with terror bombings and other attacks, raising worries about the stability of Iraq's new unity government.

On Thursday, two top U.S. generals told a Senate committee that Iraq was in danger of sliding into civil war if the sectarian violence was not contained. Adnan al-Dulaimi, head of the main Sunni alliance in the Iraqi Parliament, said Saturday that the country is in danger of falling into the "circle of a civil war."

In comments posted on a Sunni party Web site, al-Dulaimi said sectarianism is being "fed by neighboring countries that do not want stability in Iraq." He did not elaborate.

Saturday's bombings occurred in Baqouba, 35 miles northeast of Baghdad. The first blast destroyed a grocery store and the second went off about five minutes later as police cars arrived at the scene. Police said the eight wounded included seven civilians and one policeman.

Baqouba is a religiously and ethnically mixed city that has been the scene of frequent violence, including Sunni insurgent attacks on U.S. and Iraqi forces and reprisal killings and kidnappings between Sunnis and Shiites.

Iraq's Defense Ministry and police announced that 55 suspected insurgents had been captured around Mosul after a flare-up of violence there Friday. Authorities also reported the arrests of 22 other insurgents in the western city of Ramadi and two in Baghdad.

Duraid Mohammed Kashmoula, governor of Nineveh province, of which Mosul is the capital, said 20 militants were believed to have been killed during prolonged street gunfights with security forces in the city's eastern neighborhoods Friday. "The terrorists thought that police were going to run away," like they did during a major clash in November 2004, Kashmoula said.

"But this will not happen again. We will not give them that opportunity."

In other violence, two members of Saddam's former regime were shot dead in separate incidents Saturday, police said.

On Friday, gunmen killed a bodyguard of a senior Justice Ministry official in western Baghdad, and a police commando was killed by a roadside bomb in the central city of Samarra.

The U.S. military command said a soldier assigned to the 1st Marine Expeditionary Force died Saturday "due to non-hostile action" in Anbar province, west of Baghdad. It did not provide details.

At least 2,587 U.S. military personnel have died since the beginning of the Iraq war in March 2003, according to an Associated Press count.