By Kamal Naama

FALLUJA, Iraq (Reuters) - Thousands of mourners rallied on Saturday at funerals for Sunni Muslims shot by troops in demonstrations against Iraq's Shi'ite Prime Minister Nuri al-Maliki.

Troops on Friday shot dead five people in Falluja, in the Sunni-dominated western province of Anbar.

Sunnis have taken to the streets since December to protest what they call mistreatment of their minority sect, heightening fears Iraq may return to the Shi'ite-Sunni bloodletting that killed tens of thousands in 2006-2007.

The Sunni protests have been accompanied by an increase in attacks by Islamist insurgents and the Iraqi wing of al Qaeda. Four suicide bombers have struck over the last week, including one who killed a Sunni lawmaker in Falluja.

Falluja's streets filled with thousands, many taking turns to carry the coffins of slain protesters. Others waved portraits of victims or the national flag used in Saddam Hussein's era, before the U.S.-led invasion ousted the Sunni strongman.

The funerals took place as the country's parliament passed a law imposing term limits on the prime minister's post in an attempt to block Maliki's re-election, although the legislation faces legal challenges in a top court.

Iraqi authorities have tried to calm anger over the shootings by withdrawing soldiers from the city and replacing them with federal police, but protesters want more concessions.

"Withdrawing the army from the city is not enough, I do not know how this will benefit me and it won't get my brother back," said Mustafa Jamal, a relative of a slain protester.

Maliki has also tried to appease Sunni protesters by releasing more than 1,000 detainees and appointing a senior Shi'ite figure to negotiate over Sunni demands. Anbar clerics and hardline tribal sheikhs say that is not enough either.

Anbar province stretches across a third of Iraq's territory and was once al-Qaeda's base to battle against American troops.

Sunni tribes in cities like Falluja and Ramadi then turned against al Qaeda to help U.S. forces, but tribal sheikhs complain the Baghdad government has failed to provide jobs for their fighters who helped turn the tide of the war.

In a sign of Falluja's fragile security, insurgents kidnapped three off-duty Iraqi soldiers and killed their driver on the city's outskirts, security officials said.

Many Sunnis want reforms to anti-terrorism laws they feel unfairly target them and more control over a campaign against former members of Saddam's outlawed Baath party. But Sunni ranks are split with more hardliners calling for Maliki's ouster.

In another challenge to Maliki, lawmakers on Saturday passed a law limiting the prime minister to two terms. But that measure appeared a symbolic victory as it needs the president's approval and faces challenges in court. Continued...