Islamabad, Nov 24 (IANS): At least six people, including two children, were killed and 20 others injured when a blast hit a Muharram procession in Pakistan's northwest district of Dera Ismail Khan Saturday morning, police said.

The bomb was detonated by a remote control device, police said. The bomb contained an estimated eight to 10 kg of explosives placed inside a pressure cooker, Xinhua reported quoting police officials and media reports.

Qazi Jamil-ur-Rehman, deputy inspector general police of Dera Ismail Khan, 300 km from here, said four people were killed on the spot and the two died at hospital when the explosion hit the Shia procession.

The killed include two kids, he said, adding that four out of the 20 injured are in critical condition.

The blast took place around 9.55 a.m. (local time) when a bomb hidden under a garbage heap in the suburban Thoya Fazil area of the district hit a small group of some 30 Shia Muslims passing by on the way to join a main procession to mark the ninth day of Muharram, the first month of the Islamic calendar year.

The blast caused a great panic, sending people running in all directions, local media quoted eyewitnesses as saying.

All the injured have been shifted to the local district headquarters hospital. Some of the seriously wounded have been referred to a hospital in Multan city in central Punjab, hospital sources said.

Following the blast, the army has been called in to maintain order in the district and a suspect has reportedly been arrested in the nearby area.

Both Pakistani President Asif Ali Zardari condemned the attacked and called for the best possible medical treatment to the injured.