Iraqi Deputy Prime Minister Salam al-Zobaie was wounded and undergoing surgery after a suicide bomber blew himself up in a hall where he was attending Friday prayers today.
Six of Mr Zobaie's guards were killed in the second assassination attempt on a senior member of the US-backed government in a month.
One of Mr Zobaie's aides said the suicide bomber appeared to have been one of his own guards.
Brigadier General Qassim Moussawi, spokesman for security in Baghdad, told Iraqiya state television Mr Zobaie, a member of the main Sunni Arab political group, was wounded in various parts of his body in the suicide bomb attack.
"He is undergoing surgery now. His condition is not stable so far," Mr Moussawi said.
Mr Moussawi said Mr Zobaie was the target of two coordinated attacks - the suicide bomber at a prayer hall in the compound of his residence and a car bomb at his home. He said six of Mr Zobaie's security guards were killed and 15 people wounded.
Mr Zobaie, one of two deputy prime ministers, is a member of the Accordance Front, the main Sunni Arab grouping in Iraq's Shia-led national unity government. He is also a member of a well-known tribe from the Abu Ghraib area northwest of Baghdad.
One of Mr Zobaie's aides said the suicide bomber appeared to have been one of his own guards. The aide said rival factions in the tribe were feuding, one side supporting al-Qaeda militants and the other loyal to the deputy prime minister and the government.
The western province of Anbar has recently seen a surge in violence between tribes who have come out against al-Qaeda and militants who have been taking revenge on them for doing so.
Insurgents have frequently targeted leaders of the US-backed government. Last month Iraq's Shia Vice President Adel Abdul-Mahdi was wounded by shrapnel when a bomb killed six people inside the public works ministry.
Yesterday, a rocket landed yards from the prime minister's home during a news conference with the United Nations Secretary-General Ban Ki-moon.