ISLAMABAD: Police are questioning more than 200 people to determine if rioting that killed eight Christians was spontaneous or planned by a militant group, an official said Tuesday.

Another top official suggested militants fleeing an army offensive in the northwest Swat Valley were involved.

Hundreds of Muslims attacked a Christian neighbourhood in the eastern Pakistani city of Gojra on Saturday after reports that Christians had desecrated a copy of the Holy Quran.

The assault, which also torched dozens of homes, underscored the precarious existence of religious minorities in Pakistan.

Punjab province Law Minister Rana Sanaullah told The Associated Press that members of the banned Sunni group Sipah-i-Sahaba Pakistan and its al-Qaeda-linked offshoot Lashkar-i-Jhangvi have been arrested as suspected attackers.

The question is how long — or whether — they had planned the attack.

A Pakistani intelligence report some two months earlier had suggested that militant groups may be switching from suicide attacks to creating sectarian strife in cities, he noted.

‘We need to locate and arrest those who were wearing masks during the carnage,’ Sanaullah said, referring to the attackers who were covering their faces during the rioting to avoid being identified.

The demonstrations began Thursday but reached their violent zenith Saturday, allegedly after hardline clerics began making speeches against the Christians.

Authorities say an initial probe had debunked the claims that the Holy Quran was desecrated. Christians in the community attended special church services for the victims Tuesday.

Separately, Punjab province Gov. Salman Taseer, on a visit to Gojra, said ‘those who were evicted from Swat have a hand in this incident.’ Taseer offered no evidence to back up this claim.

Pakistan's army is engaged in a three-month-old offensive in Swat, a northwest valley that was once a prominent tourist destination. The military claims to have killed 1,800 suspected militants in the operation.

Christians — including Protestants and Catholics — make up less than five per cent of Pakistan's 175 million people, according to the CIA World Factbook. They generally live in peace with their Muslim neighbours.