Another U.S. soldier was wounded in the 10 a.m. attack, the U.S. military said. It gave no further details on the deaths.
At least 4,131 members of the U.S. military have died in the Iraq war since it began in March 2003, according to an Associated Press count.
Meanwhile, Iraqi leaders remain deadlocked in talks over a power-sharing dispute that is blocking U.S.-backed provincial elections. The disagreement over the oil-rich city of Kirkuk forced parliamentary officials to delay a planned vote on the provincial elections bill until Tuesday, at the earliest.
The United States considers provincial elections, which are expected to redistribute power at the local level, essential to reconciling Iraq's rival ethnic and religious communities.
But Kurds object to a measure that would equally distribute provincial council seats among Arabs, Kurds and Turkomen in Tamim province, which lies just south of their own semiautonomous region in Iraq's north.
Kurds and their allies already hold a majority on the council, and fear nic and sectarian leaders to compromise on critical issues in the interest of national reconciliation.
The Kurds - traditionally staunch allies of the U.S. and majority Shiites in Iraq - also are at loggerheads with the central government over a new oil law, which would throw out previous deals between the local Kurdish administration and foreign companies.
The bitter debate has raised concern that the tensions in northern Iraq could spark a new cycle of violence and jeopardize recent security gains. That fear was underscored this week by a series of attacks in Baghdad and surrounding areas.
The deadliest attack Monday was against an Iraqi police patrol vehicle in Mahaweel, about 35 miles (60 kilometers) south of Baghdad that killed four policemen and three civilian bystanders, according to Iraqi police.
Another roadside bomb on Palestine Street, a major thoroughfare in Baghdad, killed two Iraqis - a soldier and a civilian - and wounded seven others, said Iraqi officials, who spoke on condition of anonymity because they weren't authorized to release the information.
