BAGHDAD — Roadside bombings and gunbattles across Iraq killed nine U.S. servicemen as U.S. authorities examined a body found in a river south of Baghdad that Iraqi police believe is one of three American soldiers seized in an ambush nearly two weeks ago, officials said today.

U.S. authorities have not determined if the body found in the Euphrates River was one of three missing American soldiers from the May 12 ambush of their patrol near Mahmoudiya, about 20 miles south of Baghdad. Four Americans and one Iraqi soldier were killed in that attack.

The military said seven soldiers and two Marines were killed in separate attacks Tuesday, bring the U.S. death toll for the month to at least 80. Last month, 104 U.S. troops were killed in Iraq.

U.S. officials have warned that American casualties were likely to increase as troops made more frequent patrols during the three-month-old U.S.-led security crackdown in Baghdad.

Six of the soldiers were killed by roadside bombs and the seventh was killed by small arms fire.

The military said only that the two Marines were killed in combat operations in Anbar province.

In the town of Mandali, on the Iranian border 60 miles east of Baghdad, meanwhile, a suicide bomber walked into a packed market cafe and blew himself up today, killing 15 people and wounding 20 others, police said.

The cafe in the mixed Sunni, Shiite and Kurdish city, was usually frequented by police, but no police officers were there at the time, police said. Police said a man in his 30s wearing a heavy jacket despite the searing heat was seen walking into the cafe just seconds before the blast.

In another devastating attack, a suicide bomber blew himself up in the house of two brothers who were supporting a Sunni alliance opposed to al-Qaida in the Anbar province, killing 10 people, including the men, their wives and their children, police Lt. Col. Jabar Rasheed Nayef, said today.

The attacker, a 17-year-old neighbor, broke into the house of the two men, Sheik Mohammed Ali and police Lt. Col. Abed Ali, and detonated his bomb belt about 11 p.m. Tuesday in Albo Obaid, about 60 miles west of Baghdad.