Islamabad, Jan 8 (DPA) At least 12 people were killed and several more injured Friday in two bombings in Pakistan’s southern port city of Karachi and a tribal district near the Afghan border, officials said.

The first bombing tore through a house where explosives were being stored in Pakistan’s largest city Karachi, killing seven suspected militants.

The house, located in the Baldia Town neighbourhood, collapsed in what police believed was an accidental explosion, and officers said they suspected those killed were members of a militant group planning terrorist attacks in the country’s industrial and financial capital.

“Six corpses and some mutilated body parts have been recovered from the rubble,” said Sohail Afzal, a police officer investigating the incident.

Interior Minister Rehman Malik told reporters that the house was occupied by men from the Swat Valley in north-western Pakistan, where security forces launched an operation in the spring to quell a Taliban insurgency.

Malik said visitors from Swat arrived at the house before dawn Friday and were taken to a courtyard where the explosion took place nearly five hours later.

The same account was given by a suspect, who was injured in the blast and later captured by police, the Express News television channel reported.

Express News cited unnamed officials as saying that the suspect – identified by a single name, Imran – told investigators that three suicide bombers had put on explosive vests and one went off accidentally as its wearer was dozing.

Two unexploded suicide vests, about two dozen hand grenades and small arms with spare magazines were seized from the ruins.

Karachi’s police chief, Waseem Ahmad, said at least six people were taken into custody after the explosion. Not all those captured were present in the house at the time of the explosion.

It was thought that the suspected bombers were planning to strike mosques because it was Friday, the day when Muslims offer prayers in large numbers.

Separately, a suicide bomber blew himself up at the headquarters of the Islamic extremist group Ansar-al-Islam in the Khyber tribal district that borders Afghanistan, killing five people and injuring 10 more.

“The attack took place when the Majlis-e-Shura (Advisory Council) of our organization was holding its meeting,” said Mohammad Naeem, the spokesman of Ansar-al-Islam.

He suspected the rival militant group, Lashkar-e-Islam, of the bombing.

The blasts came after a bomb went off last week in Karachi at a religious march by minority Shiite Muslims, killing more than 40 people.