Gunmen tried to storm Pakistan’s stock exchange in the city of Karachi on Monday morning, killing at least four security officers, officials said.

       Officials reported that four gunmen drove up to the gate in front of the exchange, and that two managed to enter the parking area before all four were killed in a firefight with security forces. Officials and traders were reported to have taken shelter inside the exchange during the shooting, which lasted for almost an hour, officials said.

       In social media postings identified as belonging to the Baluchistan Liberation Army, the separatist group claimed responsibility for the attack.

       The B.L.A. is an ethnic Baluch insurgent movement in Pakistan’s Baluchistan Province, a resource-rich region that has for years been racked by violence. In recent years, the group has targeted Chinese interests in the region, which is a center for huge development projects that are part of China’s Belt and Road Initiative.