KARACHI: The Balochistan Liberation Army (BLA) later claimed responsibility in a message sent to AFP, saying an elite unit of fighters had carried out the assault.

The BLA is one of several insurgent groups fighting primarily in Balochistan province.

The group has targeted infrastructure projects and Chinese workers in Pakistan multiple times in recent years, including during a brazen daylight attack on Bejing's consulate in Karachi which killed four people in 2018.

In May last year, the BLA attacked a luxury hotel at Gwadar.

Last year, the US State Department designated the BLA as a global terrorist group, making it a crime for anyone in the United States to assist the militants and freezing any US assets they may have.

Following Monday's attack Pakistani authorities vowed to strike back against at any group found responsible for the onslaught, promising to dismantle their networks and destroy their bases.

Business continued as usual at the Karachi stock exchange after the attack.

"Trading is smooth and continuing. PSX benchmark index one of the Best Performer in Asia today so far," tweeted Mohammed Sohail, a broker at the exchange.

For a while after the attack the bodies of at least two gunmen could be seen in a pool of blood near the exchange.-AFP

Reuters adds: Insurgents from Balochistan claimed responsibility, a senior counter-terrorism official, Raja Umar Khattab, told Reuters.

The Baloch Liberation Army (BLA) had claimed responsibility in a post on Twitter but Reuters was not able to verify the authenticity of the account. Spokesmen for the group were not available for comment.

The BLA claimed responsibility in a brief message on a Twitter account set up shortly before the raid, describing it as a "self-sacrificing" attack carried out by its Majeed brigade.

The account was suspended a short time after the attack.

"We locked ourselves in our offices," said Asad Javed, who works at a brokerage in the stock exchange building, which is in a high security zone that also houses the head offices of several banks.

Javed said he was on the ground floor when he heard gunfire and an explosion and people scattered for safety.

Bukhari said that the attack could not have been carried out without the support of "hostile intelligence agencies" and India's Research and Analysis Wing (RAW) was one of their primary suspects.

"But at the moment we have to collect evidence to establish the supporters."

An aide to Pakistan's prime minister on national security matters, Moeed Yusuf, and the foreign minister, Shah Mahmood Qureshi, both said the attack was sponsored by hostile foreign elements.

The BLA's Majeed brigade also took responsibility for an attack on the Chinese consulate in Karachi in 2018.

The Pakistan Stock Exchange did not suspend trading during the attack. Its main KSE-100 index dropped 220 points briefly but later recovered and closed the day 242 points (0.7%) higher.

Copyright Business Recorder, 2020