BAGHDAD, Iraq — Iraq's prime minister imposed a daytime driving ban in Baghdad and in the province where Abu Musab al-Zarqawi was killed by American bombs, fearing insurgents will seek to avenge the death of the al-Qaida in Iraq leader.

As Iraqi and U.S. leaders cautioned that al-Zarqawi's death was not likely to end the bloodshed in Iraq, an American general said another foreign-born militant was already poised to take over the terror network's operations.

Maj. Gen. William Caldwell said Egyptian-born Abu al-Masri would likely take the reins of al-Qaida in Iraq. He said al-Masri trained in Afghanistan and arrived in Iraq in 2002 to establish an al-Qaida cell.

Al-Masri, whose name is an obvious alias meaning "father of the Egyptian," is believed to be an expert at constructing roadside bombs, the leading cause of U.S. military casualties in Iraq.

Al-Zarqawi, who was born in Jordan, was killed in a U.S. airstrike Wednesday near Baqouba, the capital of Diyala province, which is in the heartland of the Sunni-led insurgency and has seen a recent rise in sectarian violence. Baqouba is 35 miles northeast of Baghdad.

The vehicle ban will be in effect from 11 a.m. to 3 p.m. today in Baghdad and from 8 p.m. to 6 a.m. for three days starting today in Diyala, Interior Ministry spokesman Brig. Adnan Abdul Rahman said.

The ban falls during the times that most Iraqis go to mosques for Friday prayers. Bombers have been known to target Shiite mosques during the weekly religious services with suicide attackers and mortars hidden in vehicles.

Iraqi authorities imposed the vehicle ban as a security measure "to protect mosques and prayers from any possible terrorist attacks, especially car bombs, in the wake of yesterday's event," a government official said, referring to al-Zarqawi's death. The official from the prime minister's office spoke on condition of anonymity because he is not authorized to speak to media.

The U.S. military displayed images of the battered face of al-Zarqawi, Iraq's most feared terrorist, and said he had been identified by fingerprints, tattoos and scars. Biological samples from his body also were delivered to an FBI crime laboratory in Virginia for DNA testing. The results were expected in three days.

Prime Minister Nouri al-Maliki also hailed a breakthrough on the political front Thursday, gaining approval from the Iraqi parliament for three key security ministers in a move that ended a three-week stalemate among Iraq's fractured ethnic and sectarian groups.

The new Iraqi Defense Minister Gen. Abdul-Qader Mohammed Jassim al-Mifarji, a Sunni Arab, promised to work with the other security forces to stop the violence in the country.

"I will cooperate completely with the other security forces, the interior ministry, the national security, the intelligence service," he said Thursday at a handover ceremony. "We have to be one team with the multinational forces to achieve victory against terrorism."