TRIPOLI, Lebanon: Lebanese commandos, backed by helicopter gunships, seized the headquarters of an Islamist militant leader Monday, on the fourth day of clashes that have rocked Lebanon’s second city, leaving 42 people dead and some 150 wounded.

A military source confirmed that the Abdullah bin Masoud Mosque, the stronghold of Shadi Mawlawi and his partner Osama Mansour, militant commanders reportedly linked to the Al-Qaeda affiliate Nusra Front, had fallen into the hands of the Lebanese Army.