Baghdad, Iraq ? Gunmen killed an aide to Iraq’s most influential Shiite cleric and two bodyguards in a drive-by shooting outside a Baghdad mosque Friday – an attack likely to stoke tensions between the Shiite majority and the Sunni minority, officials said.

Elsewhere in the capital, a car bomb exploded near a checkpoint outside offices of Prime Minister Ibrahim al-Jaafari’s Islamic Dawa Party, killing one person and injuring at least four more, officials said. Al-Jaafari was not there at the time, party official Ayad al-Nedawi said.

Shiite cleric Kamal Ezz al-Deen al-Ghuraifi, an aide to leading Shiite cleric Grand Ayatollah Ali al-Sistani, was shot as he was about to leave al-Doreen mosque after leading prayers, according to his son, Hamid Kamal. Police Lt. Thair Mahmoud confirmed the attack.

“Gunmen in a speeding car sprayed him with machine guns,” Mahmoud said.

Two bodyguards were killed and another four were wounded, he said.

Al-Ghuraifi, in his 60s, had been a Baghdad representative of al-Sistani for the past decade, said Amer al-Hussaini, a friend of al-Ghuraifi’s and a member of al-Hawza al-Ilmiyah, the Shiites’ ancient seminary in the southern city of Najaf.

An Iraqi policeman tries to explain to a U.S. soldier what has happened at the site of a suicide car bomb attack at a checkpoint outside the offices of Iraqi Prime Minister Ibrahim al-Jaafari's Islamic Dawa Party on Friday in Baghdad, Iraq. One person was killed and at least four were injured in the attack. The prime minister was not in the building at the time of the attack, party officials said.

It was the third attack on al-Sistani aides in recent weeks.

Last week, gunmen killed Samir al-Baghdadi, who represented al-Sistani in Baghdad’s predominantly Shiite al-Amin district. In May, attackers assassinated Shiite cleric Mohammed Tahir al-Allaq, al-Sistani’s representative in the Jurf al-Nadaf area near Madain, about 14 miles southeast of Baghdad.

“These attacks are aimed at stoking sectarian tensions between Iraqis,” al-Hussaini said.

Separately, five masked gunmen stormed a Sunni mosque in the same neighborhood and kidnapped an imam, Sheik Amer al-Tikriti, during Friday prayers, police 1st Lt. Mohammed al-Hiyani said.

A Sunni-dominated insurgency has killed about 1,380 people – mostly civilians and Iraqi forces – since Prime Minister Ibrahim al-Jaafari announced his Shiite-dominated government April 28.