Ahmed al-Alwani's arrest and the deaths during the raid threaten to inflame widespread discontent among Iraq's minority Sunni Arab community and could compound the rampant violence bedevilling the country.
"Security forces attacked the residence of MP Ahmed al-Alwani in central Ramadi to arrest him this morning, sparking a battle with his guards with automatic weapons and rocket-propelled grenades," a police major told AFP, referring to the capital of Anbar province west of Baghdad.
"Five of Alwani's guards and his brother were killed and eight others wounded, while 10 security forces members were also wounded," the major said.
A police captain confirmed the details of the raid, while a doctor at the Ramadi hospital confirmed the toll.
It was not immediately clear why Alwani, in his 40s and serving his second term as an MP, was arrested, though he is a well-known supporter of Sunni Arab anti-government protesters camped on a highway near Ramadi, and has frequently spoken at the site.
Protests broke out in Sunni Arab-majority areas of Iraq late last year after the arrest of guards of then-finance minister Rafa al-Essawi, an influential Sunni Arab politician, on terrorism charges.
The arrests were seen by Iraqi Sunnis as the latest example of the Shiite-led government targeting one of their leaders.
But the demonstrations have tapped into deeper grievances, with Sunnis saying they are both marginalised by the Shiite-led government and unfairly targeted with heavy-handed tactics by security forces.
Iraqi Prime Minister Nuri al-Maliki, a Shiite, said on December 22 that the protest site near Ramadi had become a headquarters for Al-Qaeda, and called on legitimate demonstrators to leave.
"I say clearly and honestly that the sit-in site in Anbar has turned into a headquarters for the leadership of Al-Qaeda," Maliki said in remarks broadcast on state television.
He called on "those who are with them in this place who refuse sabotage and who have legal or illegal demands... to leave these camps, and leave this place, so that Al-Qaeda stays alone," adding protesters had a "very short period" in which to leave.
Sunni discontent has been a key factor in the escalating unrest in Iraq this year, boosting recruitment for militant groups, pushing them to carry out attacks and eroding cooperation with security forces.
But while the government has made some concessions aimed at placating Sunni Arabs, including freeing prisoners and raising the salaries of anti-al-Qaida fighters, underlying issues remain unaddressed.
The last major security operation at a protest site, near the northern town of Hawijah on April 23, sparked clashes in which dozens of people were killed.
Nationwide death tolls from violence has spiked, reaching a level not seen since 2008, when the country was just emerging from a brutal period of sectarian killings.
More than 6,700 people have been killed in violence since the beginning of the year, according to AFP figures based on security and medical reports.