The Thursday evening blast at a checkpoint on the eastern outskirts of Ramadi also wounded nine Iraqi security-force members and three civilians, bringing the list of victims to 25, U.S. Marine Capt. Jeffrey Pool told The Associated Press.
The attacker also died in the explosion near the flashpoint Sunni Triangle city of Ramadi, 70 miles west of Baghdad.
In an eastern Baghdad neighborhood, unidentified attackers killed five female translators working for the U.S. military late Thursday, said police Capt. Ahmed Aboud.
The translators "were heading home when gunmen driving two cars sprayed them with machine-gun fire," said Aboud on Friday. Further details weren't immediately available.
Insurgents routinely target U.S. forces and their perceived collaborators as well as members of Iraq's government, army and police — security forces the U.S. military says must gain better control of the strife-torn country before any major U.S. troop withdrawal.
In other developments:
On Thursday, hundreds of power workers shouting "No, no, to terror!" marched through Baghdad to protest attacks that have killed dozens of their colleagues, while demonstrators in the south demanded that the new petroleum minister be appointed from their oil-rich region.
The demonstrations came as negotiators for the two biggest factions in the new National Assembly worked out details of an Iraqi government that U.S. officials hope will pave the way for the eventual withdrawal of coalition forces.
Jawad al-Maliki, a negotiator from the Shiite-led United Iraqi Alliance, said talks had progressed enough for Shiite Arab and ethnic Kurd officials to agree to hold parliament's second session early next week, although no date had been set. The 275-seat National Assembly met March 16 to swear in its members.
"The negotiations were positive and very good," al-Maliki said. "In the coming days, the meetings will be continuous and decisive."
Lined up behind a black banner with the names of slain power workers, protesters demanded an end to attacks on electricity stations and oil pipelines — targets in an insurgent effort to weaken the economy and undermine the U.S.-led coalition and interim government.
At the same time, in southern Basra, more than 200 workers gathered outside a local government building to insist that the new government's oil and transportation ministers be someone from that region.
"Everyone must know that the oppressed and persecuted people of the south refuse to have their interests be ignored," protesters said in a statement given to the provincial governor, Mohammed al-Waeli.
Al-Waeli agreed, saying: "We are eager that the people of Basra and the south have clout in the new government."
Some oil workers threatened to disrupt production in the south.
"We will stop pumping the oil and go on strike for those working in the oil field and the ports if our demands aren't met," said Mohammed Abdul Hafez, a union official who was one of the demonstration's organizers.
Kurdish and Shiite negotiators debated Cabinet posts Thursday, and Abdul-Karim al-Anzi, a Shiite official, said lawmakers should be able to elect the president, two vice presidents and parliament's speaker in their session next week.
The prime minister is expected to be Ibrahim al-Jaafari, a politician from Iraq's Shiite Arab majority. Kurdish leader Jalal Talabani is likely to be named president.
One of the vice presidents will likely be a Sunni Arab, al-Maliki and al-Anzi said.
The move is an effort to reach out to the Sunni community, which is believed to be the backbone of the insurgency. Dominant under former dictator Saddam Hussein, Sunni Arabs mostly stayed away from Iraq's Jan. 30 election, some in a boycott of the vote and others in fear of attacks.
Shiite Arabs are estimated to make up 60 percent of Iraq's 26 million people, while Kurds and Sunni Arabs are each thought to be 15 percent to 20 percent.