U.S. Secretary of Defense Donald Rumsfeld arrived in Baghdad Wednesday for an unannounced visit to show U.S. support for the country's new prime minister.

Secretary Rumsfeld touched down at Baghdad's airport shortly after dawn and went directly to the fortified Green Zone in the city center to meet with his top commander in Iraq, General George Casey. After a series of briefings by senior commanders, the secretary is scheduled to meet with Iraq's president and the new prime minister, Jawad al-Maliki.

On the secretary's plane en route to Baghdad, a spokesman said the trip is intended to demonstrate U.S. support for Iraq's new government. On Monday, Secretary Rumsfeld called Saturday's election of the prime minister and several other top officials a "thrilling" and "enormous accomplishment."

Rumsfeld has come under increasing criticism from some retired generals and some members of congress for his conduct of the war in Iraq. According to the spokesman, just before leaving for Baghdad, Rumsfeld told about 15 members of Congress at a breakfast meeting not to overlook what he called Saturday's "very important milestone," and to fully fund the effort to train and equip Iraq's new security forces.