The Iraqi army has begun moving tanks and security personnel into western al-Anbar province to stop anti-government protests, after Iraqi security forces arrested Ahmed al-Alwani, a prominent Iraqi MP, during a raid on his home in Ramadi.

At least six people, including Alwani’s brother and guards, were killed in clashes sparked by the raid on Saturday, while another 18 people, including 10 members of the security forces, were injured, according to police officials and a doctor from the Ramadi hospital.

"Army troops with police special forces were trying to arrest Alwani from his house, but fierce fighting erupted. Five bodies, including one woman, were taken to Fallujah hospital," one police source told the Associated Press news agency.

The raid began after an arrest warrant was issued for Alwani - a member of the Iraqiya political party and prominent critic of Iraqi Prime Minister Nouri al-Maliki - on terrorism charges.

Alwani is a well-known supporter of Sunni Arab anti-government protesters who have been camped on a highway near Ramadi since December last year.

In his weekly, televised address on Thursday, al-Maliki said these protests must come to an end.

Sectarian tensions

Reporting from Erbil in northern Iraq, Al Jazeera's Imran Khan said Alwani's arrest was going to enflame tensions in the country.

"The reason for this is that the Sunnis in Anbar province do feel that they've not only been marginalised, but they've also been deliberately targeted by the Shia-dominated government in Baghdad. They say that their members have been arrested. They've been placed in secret prisons, that they are harrassed on an almost daily basis," our correspondent said.

Supporters of Alwani said they would escalate the situation if the lawmaker is not released within 12 hours.

AFP news agency reported that hundreds of people armed with automatic weapons protested at Alwani's home in Ramadi after the raid. "With soul, with blood, we sacrifice for you, doctor," they shouted, referring to the MP.

Hundreds of people also protested in Fallujah, east of Ramadi, police said.

Parliament speaker Osama al-Nujaifi, a Sunni, sharply criticised the arrest and described it as "treading on the core of the Iraqi constitution and a clear violation of its articles".

Speaking to Al Jazeera from Baghdad, political analyst Ahmed Rushdi said members of the Alwani tribe, which is highly influential in al-Anbar governorate, threatened to attack army camps if the lawmaker was not released.

"There will be a political [crisis] between the Sunni and Shia, which means it will be a sectarian issue," he said.

Source: Al Jazeera and agencies