A suicide bomber attacked the United Nations World Food Program office in the Pakistani capital Islamabad, killing three people and wounding several, a senior police official said.
"It was a suicide blast," Bani Amin, deputy inspector general of police operations, said at the tightly guarded WFP office in a residential area of the city.
One of the dead was an Iraqi national. The other two were Pakistani women, and at least five Pakistanis were wounded, he said.
A witness said the blast went off shortly after a truck entered the compound. The U.N. office was highly secured leading to speculation that the bombing could have been an inside job.
Battling bombs
Pakistan is battling Islamist militants who have set off numerous bombs in towns and cities aimed at the security forces as well as government and foreign targets.
The WFP provides food to millions of impoverished Pakistanis.
The agency was recently involved in providing relief to about 2 million people displaced by an army offensive against militants in the Swat valley, northwest of the capital.
"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 office.
"All of a sudden, a smoke cloud enveloped the building and we came out where wounded people were lying."
Two foreign U.N. workers were killed in a suicide car bomb attack on a hotel in the northwestern city of Peshawar in June.
The army has made significant progress against militants in the Swat valley and elsewhere in the northwest and Interior Minister Rehman Malik says the back of the Pakistani Taliban has been broken.
But the militants 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