Pakistan's Interior Minister Rana Sanaullah on Friday hinted that foreign hands could be involved in the attack on Karachi Police Office (KPO), media reports said.

At least two terrorists were killed during an ongoing exchange of fire in and outside the office of the Karachi police chief as militants stormed the building located on Sharea Faisal, media reports said.

At least one police officer has been martyred in the attack while an Edhi volunteer has been injured, Samaa TV reported.

Sanaullah said that he has received a briefing on the attack from the Inspector General of Sindh Police and the Sindh Chief Secretary, the report said.

"Only one terror outfit could be behind the attack," he stressed.

Sanaullah added that as per what he has been told, there were six to seven terrorists who had stormed the KPO through its front door, Samaa TV reported.

The minister said the terrorists lobbed grenades to gain access to the police office.

He said as per the Karachi top cop, the terrorists have reached the third floor (the top floor of the building) where armed guards and other police officers had engaged the attackers, Samaa TV reported.

"But the situation is not clear," he added.

Asked whether he had any knowledge about a threat to the KPO, Sanaullah denied any such threat alert.

"There was a general threat of terrorism across the country but there was no specific threat for this office," he added.

"Once police and rangers enter the building, they will be able to neutralize the terrorists," the minister said quoting Karachi's top cop.

Asked if the attackers were armed with heavy weapons, he said that while they knew about the grenades which had exploded, they believed that one rocket-propelled grenade was also possibly fired, Samaa TV reported.

He added that it is possible that some of the attackers could be wearing explosives-laden suicide vests. (KB/IANS)