The attack on parliament was a rare strike at the heart of the Green Zone
A Sunni lawmaker in Iraq could face arrest and charges over allegations he was involved in a 2007 bomb attack on the country's parliament.
Iraq's Shia-led government may now seek to have Mohammed al-Daini's immunity revoked after a warrant was issued.
Alleged confessions obtained from two bodyguards linked Mr Daini to the attack, in which seven people died in a parliamentary canteen.
He condemned the bodyguards' arrest and pledged to respond to the accusations.
The Associated Press news agency said Mr Daini described the allegations as "untrue and baseless".
"They have the right to say anything they like and I have the right to give my answer," he told Reuters.
The MP was reportedly put under effective house arrest at a hotel in Iraq's fortified Green Zone.
Announcing the allegations at a news conference, a military spokesman played recordings said to be taped interviews with the two bodyguards - one of whom was Mr Daini's nephew.
One of the men in the video recording, named as Riad Ibrahim al-Daini and said to be the MP's nephew, gave details of how the lawmaker allegedly helped facilitate the attack on parliament.
The attack in April 2007 killed eight people, among them three MPs.
"The suicide bomber entered parliament with an authorisation paper from Mohammed al-Daini and blew himself up at the parliament," the video testimony said, according to the AFP news agency.
The nephew also accused Mr Daini of involvement in a string of attacks during a bitter period of sectarian violence in Iraq.
"When 11 of Daini's security guards were killed... he asked militant groups to abduct about 100 people - he wanted 10 people for each of his guards," Riad al-Daini said on video, Reuters said.
Mr Daini is a Sunni Muslim MP with Iraq's National Dialogue Front party. He was elected to parliament in 2005 to represent Diyala, a mixed Sunni-Shia area which has long been the scene of sectarian violence.
Iraq's government, headed by Prime Minister Nouri Maliki, is led by a coalition of Shia Muslim parties.
Supporters of Mr Daini accused the ruling Shia majority of effectively persecuting their Sunni opponents, AP reported.