Pakistan on Thursday mourned the 47 victims of its deadliest plane crash in four years, among them a rock star turned Muslim evangelist, two infants and three foreigners, as officials sought to pinpoint the cause.

Engine trouble was initially believed responsible, but many questions remain, stirring new worries about the safety record of money-losing state carrier Pakistani International Airlines.

The ATR-42 aircraft involved in the crash had undergone regular maintenance, including an "A-check" certification in October, airline chairman Muhammad Azam Saigol said.