KARACHI: Hundreds of mourners went on the rampage in the restive Pakistani city of Karachi yesterday after the funeral of Shi'ite Muslims killed in a gun attack, targeting two American fast food restaurants and smashing vehicles.

The violence occurred after funeral prayers attended by more than 5,000 people for two of the nine Shi'ite Muslims killed by unidentified gunmen outside a mosque in the city on Saturday.

The assailants fled and no group has claimed responsibility for the attack.

It appeared, however, to be a fresh outbreak of the Muslim sectarian violence that has dogged Pakistan for the past decade.

Police and witnesses said that after yesterday's funerals, crowds of angry youths attacked two Kentucky Fried Chicken restaurants, two petrol stations and smashed up cars.

"The crowd did not try to set them ablaze, but only hurled stones, smashing their glass," Karachi police chief Tariq Jameel said.

"There is no apparent reason to attack the KFCs or any other places. But there was a lot of anger and anguish among the mourners. The situation is now under control."

It was unclear why a US restaurant chain should be targeted, but Shi'ite Muslim groups are close to Iran and traditionally anti-American.

"We will avenge the killings," demonstrators shouted as they burned tyres.

Smaller protests were held in the capital, Islamabad, and in the central town of Multan, where protesters said peace in Pakistan had been disrupted ever since the government decided to support the US-led war on terror.

Earlier, police said they had stepped up security in Karachi after Saturday night's shootings.

Hundreds of paramilitary rangers patrolled volatile areas, including mosques and other places of worship, on vehicles mounted with heavy machine guns.