MULTAN Up to 35 people were killed and 46 wounded on Thursday when a suspected suicide bombing ripped through a crowd of worshippers outside a Shia mosque on Thursday, reports DawnNews TV.

Police said the blast targeted dozens of people converging on the Al-Hussainia mosque after dark in the town of Dera Ghazi Khan, shortly before a religious gathering.

'We have arrested 16 suspects for questioning in connection with the blast,' Shaukat Javed, the police chief of Punjab province, told AFP by telephone.

The suspects were picked up in different areas outside town, he said.

Although there was no immediate claim of responsibility for Thursdays blast, police were swift to blame sectarian extremists following a wave of similar violence in the country.

'Ninety-nine per cent it looks like a suicide attack,' said Shaukat Javed, the highest ranking police commander in Punjab province.

'The blast occurred when a group of about 50 Shia Muslims were returning to the mosque after visiting a nearby place,' said Javed.

'The explosion occurred just 50 feet short of the mosque. It is a terrorist attack aimed at Shias to create unrest,' he added.

District health official doctor Fazal Karim confirmed that 13 bodies were brought to the local hospital, including those of two children and a woman, but said he did not know how many dead may have been counted elsewhere.

Medics said six people with serious injuries were rushed for specialist treatment in Multan, the closest sizeable town 100 kilometres west of Dera Ghazi Khan.

But of 40 people hurt in the blast, most were released after first aid, the officials said.

'The initial report is that it was a suicide attack. He exploded himself in the crowd. Body parts have been found and sent to the hospital,' district police chief Athar Mubarik told reporters.

'The attacker was wearing a jacket carrying 12 to 14 kilograms of explosives,' he added.

The powerful blast caused serious damage to the mosque and another nearby Shia holy place in the town, local police official Mohammed Ahsan said.

Shia faithful are observing the last week of a 40-day mourning period to commemorate the death of their revered Imam Hussein, who was killed at Karbala, in present day Iraq, in 680 AD.

Rescue workers were seen trying to clear a crowd out of the way to let ambulances pass in darkness, in footage broadcast by private television channels.

The bombing is the deadliest since a suicide attack struck a meeting of anti-Taliban tribal leaders in the northwest border areas near Afghanistan and killed at least 40 people last October 10.