Six people were killed on Friday when a blast caused a house to collapse in Pakistan's economic hub Karachi, police said, although the exact cause of the explosion was not immediately clear.
"There was a blast in a house in (Karachi's) Baldia Town in which six people were killed. The house collapsed. We are trying to ascertain the exact nature of the blast," said senior police official Abdul Majeed Dasti.
He said hand grenades and a Kalashnikov rifle were also found at the scene, which suggest that the house may have been used by militants.
Forty-three people were killed in Karachi -- Pakistan's largest city -- in a bombing blamed on militants during a religions procession last month.