Four suspected terrorists stormed the Karachi Stock Exchange building and were inside for a while before engaging in a gunfight with security forces.
At least five people have reportedly been killed in a firing incident and grenade attack at the Pakistan Stock Exchange located on main I.I. Chundrigar in Karachi.
There were no reports of any wounded among the brokers and employees inside the exchange and a separatist militant group from a neighboring province later claimed responsibility for the attack.
It is not clear if more assailants were involved and a search of the premises is continuing.
A tweet from the official Twitter page of the Pakistan Stock Exchange said, "There was an attack on the PSX compound earlier today".
Security personnel examine confiscated ammunition from attackers outside the Stock Exchange Building.
The same militant group previously mounted a deadly attack on the Chinese consulate in Karachi in November 2018 and in May previous year attacked a hotel in Gwadar, a port city in Balochistan used by Chinese working on China-Pakistan Economic Corridor projects.
"An investigation has been launched and very soon we will reach their masterminds", Interior Minister Ijaz Ahmad Shah said in a video message posted after the attack.
The attack on the building located in the heart of Karachi's financial district, where the Pakistan State Bank is located as well as the headquarters of several national and global financial institutions, left two guards and a police officer dead, officials say.
"The attackers came in a silver Toyota Corolla and were stopped by the police at the gate outside where the exchange of fire took place", said Ghulam Nabi Memon, additional IG, Sindh police.
This month, three explosions on the same day claimed by a little-known separatist group killed four people including two soldiers in the southern province of Sindh, of which Karachi is capital.
The Pakistan Stock Exchange in Karachi is the country's largest.
Pakistan's government says BLA militants had attempted to takeover China's consulate in Karachi in 2018.
Khan also shared that trading was not affected by the attack and continued even during the attack and was still underway.
But the situation has largely stabilised in recent years following operations by security agencies against armed political outfits and Islamist militants.