SUICIDE bombings ripped through two mosques in Pakistan, killing at least 57 people and injuring dozens more as believers marked the birthday of the Prophet Mohammad, police and health officials said. No group immediately claimed responsibility for the blasts, one of which was reported to have trapped dozens under rubble. A surge in militant attacks in Pakistan's western provinces has cast a shadow on election preparations and public campaigning in the run-up to January's general elections, but until now the attacks had mostly targeted security forces. The first blast, in Mastung in the southwestern province of Balochistan, killed at least…