An Iraqi soldier waves his national flag Monday from top of an armored vehicle in front of the gates to the Basra Palace complex in Basra, Iraq. Iraqi soldiers hoisted the nation's flag over the Basra palace compound Monday after British troops began withdrawing from their last garrison in the city, a move that will hand control to Iraqi forces.

Baghdad ? Iraq’s prime minister said Monday he expects the U.S. ambassador and military commander to give his government favorable marks when they report to Congress next week and predicted passage of a law soon that could return more Sunnis to government jobs.

To the south, Basra was reported calm Monday after British soldiers abandoned their last outpost there, leaving the country’s second largest city largely in the hands of Iranian-backed Shiite militias.

Also Monday, the U.S. command said an American soldier was killed and three others injured when a roadside bomb blew up next to their patrol on Sunday outside of Baghdad. No further details were released.

The latest casualties occurred a week before U.S. Ambassador Ryan Crocker and Gen. David Petraeus are to report to Congress on political and security progress since President Bush ordered about 30,000 additional troops to Iraq early this year.

Prime Minister Nouri al-Maliki told reporters Monday that his government was making progress toward national reconciliation and that both Crocker and Petraeus “are witnessing this progress.”

“I expect that the positive developments will be, for sure, reflected in the report to Congress on Sept. 15,” al-Maliki said.

The prime minister spoke before leaving for al-Asad Air Base to confer with Bush, who flew to the remote air base for a firsthand assessment of the war before the coming debate over the U.S. troop buildup.

U.S. officials are expected to tell lawmakers that the troop increase has brought some improvements in security but that progress toward power-sharing deals among Sunnis, Shiites and Kurds has lagged behind.

Sen. Hillary Clinton and Sen. Carl Levin, chairman of the Senate Armed Services Committee, have blamed al-Maliki and called for him to be replaced.

Stung by those calls, al-Maliki said his critics have overlooked the achievements of his government, including a reduction “to a large extent” in sectarian reprisal killings.