Updated

Tens of thousands of Sunni protesters blocked a major highway in western Iraq on Friday, as an Al Qaeda-affiliated group called on Sunnis to take up arms against the Shiite-led government.

The protest comes at a time of mounting sectarian tensions in Iraq. Minority Sunnis complain of official discrimination against them, and the arrests of bodyguards of a senior Sunni politician in December have sparked weekly anti-government demonstrations.

Friday's rallies were staged in the cities of Fallujah and Ramadi that straddle the highway running through Anbar province, a former Al Qaeda stronghold that saw some of the fiercest fighting against U.S. forces during the Iraq war.

Friday's turnout appeared to be among the largest since the protests began in December.

In Fallujah and Ramadi, demonstrators performed Muslim noon prayers, the highlight of the religious week, on the highway, which links Iraq with Jordan.

Last week, at least five protesters and two Iraqi soldiers were killed in clashes in Fallujah and on Friday, demonstrators held up pictures of some of those killed.

Sunni cleric Abdul-Hameed Jadoua told the crowd that "the blood of the martyrs was shed so that the dignity of our Iraq and our tribes will be restored."

He demanded that soldiers be put on trial for killing protesters and said the army must stay out of the area. "From this place, we tell the government that we do not want to see a soldier from now on, not only in Fallujah, but in all its suburbs and (surrounding) villages," he said.

The cleric appeared to be rebuffing a call to arms. "I tell the young people that we do appreciate your zeal .... but you should be disciplined and adhere to the directives of the clerics and tribal leaders so that we act in a reasonable way," he said.

Al-Qaida has expressed support for the protests. On Friday, an Al Qaeda-affiliated group, the Islamic State of Iraq, called on Sunnis to resort to violence against the government.

Sunnis can either bow to Shiites or take up arms and restore "dignity and freedom," said spokesman Mohammed al-Adnani in an audio statement posted on the group's website.

Prime Minister Nouri al-Maliki has suggested that Al Qaeda and members of Saddam Hussein's ousted regime are involved in the demonstrations. Organizers insist they have no links to terror groups.

The protesters seek the release of Sunni detainees held in Iraqi jails and the cancellation of a tough counterterrorism law and other policies they believe overwhelmingly target Sunnis. Many of the demonstrators link their cause to the broader Arab Spring uprisings and are calling for the ouster of the government.

Al-Maliki has released hundreds of detainees in a concession to the protesters. On Thursday, the prime minister was quoted as saying he would address what he described as "legitimate demands." He said a committee dealing with these issues has made progress.