Islamabad: A suicide bomber dressed as a paramilitary soldier attacked an office of the UN World Food Programme (WFP) in the Pakistani capital on Monday killing five people and wounding several, officials said.
Pakistan is battling Islamist terrorists who have set off numerous bombs in towns and cities aimed at the security forces and government and foreign targets.
"I went to my office on the first floor and as I sat on my chair there was a huge blast," WFP official Arshad Jadoon told Reuters outside the tightly guarded office in a residential area of Islamabad.
"All of a sudden, a smoke cloud enveloped the building and we came out where wounded people were lying," Jadoon said.
Officials at city hospitals said five people had been killed.
The blast led to a brief spate of selling at Pakistan's main stock market.
"There was slight profit-taking immediately after the news broke but the market quickly recovered," said Sajid Bhanji, a dealer at brokers Arif Habib Ltd.
Police said one foreigner, an Iraqi, was among the dead while the WFP said three of its staff had been killed and several wounded.
The United Nations temporarily closed its office in Pakistan after the blast for security reasons, a UN spokeswoman said.
Two foreign UN workers were killed in a suicide car bomb attack on a hotel in the northwestern city of Peshawar in June.
The army has made progress against terrorists in the northwest and Interior Minister Rehman Malik says the back of the Pakistani Taliban has been broken.
But the terrorists have struck back with several bomb attacks in recent days as the army prepares to launch an offensive on the Pakistani Taliban's main bastion in the South Waziristan region on the Afghan border.
The bomber was disguised as a paramilitary soldier and got into the WFP compound after asking a guard at the gate if he could use a toilet, Malik told reporters at the scene.
"They are like a wounded snake," Malik said. "We expected they would attack some specific places to put the government under pressure."
More bombs expected
Captured terrorists had told interrogators some bombers had been sent off on missions last month, Mali said.
"So in coming days, two or three suicide bombings are expected," he said. Malik said the bombers were trying to destabilise the country but the nation was united against them.
"In a matter of a few days we'll take action against them as we took in Swat, Bajaur and Mohmand," Malik said, referring to three northwestern areas where the security forces have attacked and pushed back the militants.
He did not elaborate. The WFP provides food to millions of impoverished Pakistanis. The agency was recently involved in providing relief to about two million people displaced by an army offensive against militants in the Swat valley.
"This is a terrible tragedy for WFP, and for the whole humanitarian community in Pakistan," said WFP Deputy Executive Director Amir Abdulla, speaking from agency headquarters in Rome.
There was no claim of responsibility for Monday's attack on the WFP office, which is several hundreds metres (yards) from the Islamabad home of President Asif Ali Zardari.
Zardari moved into the official presidential residence soon after his election last year for security reasons.