Thousands of Iraqis demonstrated against Syrian President Bashar al-Assad in a protest on Friday in the mostly Sunni town of Heet, condemning a bloody crackdown by his regime.

The protesters, who gathered outside Al-Faruq mosque in the centre of the western town, shouted slogans describing the Syrian leader as a "coward" and "the enemy of God," and called for violent resistance against his rule.

"This prayer is to support our brothers in Syria against Bashar al-Assad," said Ahmed Awwad, who led the demonstrators in prayer outside the mosque in Heet, around 160 kilometres (100 miles) west of Baghdad on the main highway to Syria.

"We should all resist this ruler, and all Arabs should send fighters to Syria. This stance is a religious duty. We call on Arab and Islamic countries to issue a fatwa against this regime and to announce jihad against it."

The protesters, who numbered around 4,000 according to an AFP journalist at the scene, held up banners referring to their "brothers" in Syria, saying "victory is near".

"This protest is the least we can do," said Abdulrazzaq Rahim al-Heeti, a professor of Islamic economics at Baghdad University. "This is a religious duty because what is happening in Syria is beyond anything we can imagine."

Heet lies in Anbar province, where the vast majority of residents are Sunni Arab, in contrast to Iraq's Shiite Muslim majority. Syria, by contrast, is governed by Assad's Alawite minority, an offshoot of Shiite Islam, but the majority of the population is Sunni.

More than 7,500 people have died in an 11-month uprising against Assad's regime, according to the UN.

While Iraq has largely shied away from imposing punitive measures against Syria, Prime Minister Nuri al-Maliki has called for "change" and "free elections" there.