Armed men attacked the Pakistani stock exchange in the southern city of Karachi, killing at least two people and injuring others, local media reported.
Burglars broke into the exchange after launching a grenade attack at the building’s main gate.
The latest reports quote the police saying they have killed all four heavily armed gunmen and are searching the area.
Baloch Liberation Army militants say they were behind the attack.
Baloch ethnic groups fought against a long-standing insurgency for a separate homeland and a larger share of resources in Pakistan’s Balochistan province.
Pakistan has suffered years of militant violence, mainly by Islamic groups, but attacks like this have become rare in recent years.
‘They opened fire on everyone’
Monday’s attack began when militants armed with automatic rifles threw a grenade and started shooting at a security post outside the stock exchange.
“They arrived in a silver Corolla car,” Karachi police chief Ghulam Nabi Memon told Reuters.
Guards struck back, killing the four attackers, officials say, but police and security officials are feared among the victims.
It is not clear whether more attackers were involved and a search of the facility continues. The Pakistan Stock Exchange said in a statement that the situation “is still unfolding”.
Its director, Abid Ali Habib, said the armed men left the parking lot and “opened fire on everyone”.
Reports say that most people managed to escape or hide in locked rooms. Those inside the building were being evacuated from the back door, Geo TV reported.
The stock exchange has offices for hundreds of financial institutions and is located in a high security area along with the headquarters of banks and other companies.