A sister of Iraq's new Sunni Arab vice president was killed Thursday in a drive-by shooting in Baghdad, a day after the politician called for the Sunni-dominated insurgency to be crushed by force.

In southern Iraq, a bomb hit an Italian military convoy, killing four soldiers — three Italians and a Romanian — and seriously injuring another passenger, officials in Rome said. The bomb struck the convoy near an Italian military base in Nasiriyah, a heavily Shiite city 200 miles southeast of Baghdad, said local Iraqi government spokesman Haidr Radhi.

Elsewhere, a U.S. jet fired two missiles at insurgent positions in Ramadi, U.S. officers said. Fighting also broke out northeast of Baghdad between Iraqi forces and insurgents, killing several Iraqi policemen and civilians.

CountryWatch: Iraq

The violence came as Secretary of State Condoleezza Rice and Defense Secretary Donald H. Rumsfeld visited Baghdad to meet with officials in Iraq's new government. Nouri al-Maliki, a Shiite hard-liner recently tapped as Iraq's prime minister, is trying to form a national unity government aimed at stopping a wave of sectarian violence.

Al-Maliki has 30 days to assemble a Cabinet from divided Shiite, Sunni and Kurdish parties. The most contentious question will be filling key ministries that control security forces amid demands to purge them of militias blamed for the rise in bloodshed.

Mayson Ahmed Bakir al-Hashimi, 60, whose brother, Tariq al-Hashimi, was appointed by parliament as vice president Saturday, was killed by gunmen in a sedan as she left her southwestern Baghdad home with her bodyguard, said police Capt. Jamel Hussein. The bodyguard also died.

It was the second recent killing in Tariq al-Hashimi's immediate family. On April 13, his brother, Mahmoud al-Hashimi, was shot while driving in a mostly Shiite area of eastern Baghdad.

Mayson al-Hashimi had worked on the government's audit commission and was married with two grown children. The television station Baghdad, owned by the vice president's Iraqi Islamic Party, showed family photos of her wearing an orange headscarf and footage of her bullet-riddled white SUV, while playing mournful music.

"What astonished us is that they targeted a woman. This shows how wicked the attackers are," Ziyad al-Ani, a senior official in the Iraqi Islamic Party, told The Associated Press. He said the killings "by the enemies of Iraq" will fail in their goal of driving al-Hashimi and his party from government.

The party is one of three major Sunni political groups in the Iraqi Accordance Front, which won 44 seats in the Dec. 15 parliamentary election.

On Wednesday, Tariq al-Hashimi called for Iraq's insurgency to be put down by force. Shiites had demanded that Sunni officials make such a statement to demonstrate their commitment to building a democratic system.

Al-Hashimi also shrugged off a video released this week by Abu Musab al-Zarqawi, during which the Al Qaeda in Iraq leader tried to rally Sunnis to fight the new government and denounced Sunnis who cooperate with it as "agents" of the Americans.

"I say, yes, we're agents. We're agents for Islam, for the oppressed. We have to defend the future of our people," al-Hashimi said at a news conference with President Jalal Talabani, a Kurd, and his fellow vice president, Shiite Adil Abdul-Mahdi.

All three Iraqi leaders met with Rice and Rumsfeld on Wednesday.

On Thursday, al-Maliki met with Iraq's most powerful Shiite cleric, Grand Ayatollah Ali al-Sistani, in the holy city of Najaf. Al-Sistani has played a big role in restraining Shiite anger in the face of Sunni insurgent attacks that have pushed Iraq toward civil war. Top politicians, especially Shiite ones, often seek al-Sistani's advice.

Afterward, the cleric said he urged the prime minister to form a government with politicians who put Iraq's national needs ahead of "their personal, party or sectarian interests."

More important, al-Sistani said, the government must improve security by ending widespread bombings, drive-by shootings and kidnappings, reduce government corruption, and restore electricity and clean drinking water to many people.

After the meeting, al-Maliki said he was determined to form a government that includes Shiites, Sunnis and Kurds and to disarm militias aligned with Iraq's political parties.

Al-Maliki also met in Najaf with anti-American Shiite cleric Muqtada al-Sadr, who praised the new government and urged it to set a withdrawal timetable for U.S. forces.

Al-Sadr denounced the Rice-Rumsfeld visit as "a clear interference in Iraqi affairs."

The clashes northeast of Baghdad occurred when insurgents attacked four Iraqi police checkpoints in Baqouba, a Sunni-Shiite city 35 miles northeast of the capital, police and residents said. Five Iraqis were killed — five policemen and two civilians — said Dr. Ahmed Foad, director of a local morgue. U.S. forces have been gradually turning over security responsibilities to the Iraqis in Baqouba.

In Ramadi, 70 miles west of Baghdad, U.S. forces exchanged fire with insurgents who attacked with small arms and shoulder-fired rockets from a former train station and a nearby building.

Lt. Col. Ronald Clark, commander of the 1st Battalion, 506th Infantry Regiment, said a U.S. jet fired two laser-guided missiles at the buildings and U.S. forces returned fire with mortars and rockets, killing eight of the attackers.

In a separate incident in Ramadi, one Iraqi soldier was killed during a fire fight with insurgents, army officers said.

A roadside bomb in Baghdad hit an Iraqi army patrol, killing a soldier, police said.

The bodies of 16 Iraqis who had been kidnapped and tortured were found Thursday in Baghdad and other cities, police said.

At least 141 Iraqis have been killed in insurgency- or sectarian-related violence since al-Maliki was tapped as prime minister Saturday and asked to form a new government.

Insurgents have targeted prominent men and women politicians in the past. On April 17, the brother of another leading Sunni politician, Saleh al-Mutlaq, was found dead after he was kidnapped.