The gunmen stormed a security post at the gate and fought their way into the car park [Source: Reuters]

Four gunmen attacked the Pakistani stock exchange in Karachi, killing two guards and a policeman and wounding seven others before being shot dead.

The assailants launched a grenade attack at the main gate to the building and opened fire but police say they failed to make it to the trading floor.

Staff took refuge in locked rooms and many were evacuated as security forces put an end to the assault.

Militants from the Baloch Liberation Army say they were behind the attack.

Ethnic Baloch groups have fought a long-running insurgency for a separate homeland and a greater share of resources in Pakistan’s Balochistan province.

The director-general of the paramilitary Sindh Rangers force, Omer Ahmed Bukhari, said all the attackers had been killed within eight minutes.

“They had come to carry out an attack inside the building and take hostages inside,” he told a news conference.

He said the gunmen had brought supplies of food as well as weaponry, suggesting they were prepared for a siege.

Pakistan has suffered years of militant violence, mostly by Islamist groups, but attacks such as this one have become rare in recent years.