Baghdad, Iraq ? A roadside bomb ripped through a U.S. military convoy Tuesday, killing three Marines and providing graphic evidence that the formal end of the U.S. occupation has not halted attacks on American forces in Iraq.

The roadside blast in eastern Baghdad was the first fatal attack on U.S. troops since American administrators transferred sovereignty to the interim Iraqi government.

Two Marines were wounded in the blast, which occurred on a four-lane highway in the Rustamiyah district. Also Tuesday, assailants fired on a U.S. patrol in Baghdad’s Azimiya district, once a stronghold of Saddam Hussein’s Baath party.

The Iraqi Interior Ministry said an Iraqi civilian was killed in the Azimiya attack, but there were no American casualties.

Despite the end of the occupation, about 160,000 foreign troops — most of them Americans — remain in Iraq to provide security and train Iraq’s new security services. Some Iraqis believe genuine sovereignty won’t resume until foreign troops leave.

U.S. officials had warned that the transfer of sovereignty would not stop the anti-American insurgency right away. However, officials hope that in time, Iraqis will accept that they are in charge of their country and the attacks will subside.

More deaths

Also Tuesday, a police officer and a civilian were killed when assailants attacked a police station in Mahmoudiyah, 20 miles south of Baghdad. Witnesses said gunmen recited verses from the Quran before the attack.

A roadside bomb exploded Tuesday in the northern oil center of Kirkuk as a Kurdish district police chief was heading to work. The police chief and two others were wounded and his bodyguard was killed, police said.

Insurgents fired five mortar rounds Tuesday at a U.S. base near Balad, 50 miles north of Baghdad, wounding five Iraqis, said Sgt. Wayne Marlow, a military spokesman.

In Baghdad, Allawi told his first press conference since the transfer of sovereignty that the Iraqi Cabinet was discussing emergency measures to cope with the security crisis. He said he would announce details later this week.

Iraqi media have speculated the measures could include curfews and curbs on public demonstrations — at least in areas of the country where the insurgency is active.

Hostages freed

Meanwhile, an Iraqi extremist group freed three Turkish hostages, Turkey’s Foreign Minister Abdullah Gul said. Al-Jazeera TV reported the group was releasing the hostages “for the sake of their Muslim brothers.”

Jordanian terror mastermind Abu Musab al-Zarqawi, whose followers killed American Nicholas Berg last month and South Korean Kim Sun-il last week, claimed to have abducted the Turks.

Another militant group announced that it had killed Spc. Keith M. Maupin, 20, of Batavia, Ohio, because the United States had not changed its policy in Iraq. The U.S. military said it could not confirm whether the man shown in a murky videotape was Maupin.

Another U.S. service member, Marine Cpl. Wassef Ali Hassoun, also was reported kidnapped in a tape sent to Al-Jazeera.