KARACHI (Reuters) — Four gunmen attacked the Pakistan Stock Exchange (PSX) building in the city of Karachi on Monday but security forces soon killed them all, police said. Two other people were also killed, the military said.

“The situation is still unfolding and management, with the help of security forces, is managing the security and controlling the situation”, the PSX stated on Twitter.

The gunmen attacked the building, which is in a high security zone that also houses the head offices of many private banks, with grenades and guns, Karachi police chief Ghulam Nabi Memon told Reuters. The attackers initially threw a grenade then opened fire on a security post outside the building. The four were killed when security forces posted there responded.

There was no immediate claim of responsibility. Pakistan has long been plagued by Islamist militant violence but attacks have become less frequent in recent years.

The PSX was established on 11 January 2016 after the merger of the Karachi, Lahore and Islamabad. PSX’s origins were laid with the establishment of the Karachi Stock Exchange in 1947, the Lahore Stock Exchange in 1970 and the Islamabad Stock Exchange in 1992. As of 23 February 2018, there were 559 companies listed in PSX and the total market capitalization was $84 bln. Market cap lowered to $50 bln by January 2020 following rupee devaluation.