BAGHDAD, Iraq (CNN) — Fourteen Marines and a civilian interpreter were killed Wednesday when their amphibious assault vehicle struck an improvised explosive device about 2 kilometers (1.2 miles) south of Haditha, Iraq, military officials said.

A Marine was also injured. The Marines were assigned to the 2nd Marine Division.

Wednesday’s attack follows the killings of six Marines Monday in Haditha, which is in northwest Iraq.

Another Marine was killed in a suicide car bombing in nearby Hit on Monday, the Marine Corps said.

This week’s Marine deaths brought the number of American troops killed in the Iraq war to more than 1,800, according to U.S. military reports.

All seven of Monday’s casualties were assigned to Regimental Combat Team 2, part of the 2nd Marine Division, 2nd Marine Expeditionary Force.

Haditha and Hit are Sunni Arab cities along the Euphrates River about 135 miles and 95 northwest of Baghdad respectively. Both have been the subject of recent efforts by U.S. and Iraqi troops to clear out insurgents.

They are in sprawling Anbar province, which stretches from the western environs of Baghdad to the Syrian, Jordanian and Saudi borders.

The province has been a hotbed of insurgents and jihadists from other Muslim countries since the U.S.-led invasion that toppled Iraqi leader Saddam Hussein in 2003.

U.S. convoy hit

A suicide car bomber attacked a U.S. military convoy Tuesday as it traveled though an underpass beneath al-Tahrir Square in Baghdad, wounding 29 people, Iraqi police said. Fifteen vehicles were destroyed.

In Baquba, about 30 miles north of Baghdad, police said gunmen killed a Diyala province Health Ministry official and his driver Tuesday near Diyala Medical College.

Dr. Abdul Hassan Mehdi was director of Khalis General Hospital in the town of Khalis, police said.

Also in Baquba, a bomb attack on a police convoy killed a police officer and a child Tuesday, police said. Seven police and a civilian were wounded.

Terror group commander captured

Iraqi police have captured a top commander of Ansar al-Sunna, a terrorist group blamed for last year’s suicide bombing at a U.S. military mess hall in Mosul that killed 22 people, including 14 U.S. troops.

A U.S. military statement released Monday said Majid Mohammed Ahmeen, the group’s commander in Diyala province and its self-proclaimed emir, was picked up along with a dozen other Ansar al-Sunna members in a series of raids in July. All are being held by coalition forces in Baquba.

Spokesman Maj. Steve Warren said Iraqi police also seized videotape during the raids that shows insurgents carrying out attacks.

Two commanders of Ansar al-Sunna’s assassination cells — Abass Hussain Faissal and Rahd Mohamed Mahmood — were among those captured during the raids.

The military statement said those cells have been linked to at least 20 assassinations, including the death of Kathim E-Ekza, a member of the Khatoon city council.

According to the statement, Ahmeen coordinated with al Qaeda in Iraq and the Revolution of 1920 Group to conduct complex attacks in Baquba and throughout Diyala province.