PESHAWAR, Pakistan -- Two homicide bombers dressed in burqas blew themselves up Saturday at a Pakistani food distribution center, killing 41 people in an attack that targeted people fleeing military offensives in the northwest, officials said.

The United Nations said it was temporarily suspending its programs helping displaced people in Kohat and neighboring Hangu as a result of the bombings.

The blasts occurred at a food distribution point, but there were conflicting reports whether the victims were lining up for food or being registered. The center in the Kohat region is sometimes used by foreign humanitarian groups, including the World Food Program, to deliver aid.

Meanwhile, the Pakistani army admitted that civilians were killed in an airstrike last Saturday in the northwest that supposedly targeted militants. It did not say how many had died, but apologized in a rare acknowledgment of an error that could help reduce anger among local tribes, whose support it needs to defeat the Taliban and Al Qaeda.

The two homicide bombers struck six minutes apart at the center in the Kacha Pukka area of Kohat, a tribally administered region close to the Afghan border. They were dressed in burqas, the all-encompassing veil worn by conservative Muslim women in parts of Afghanistan and Pakistan, local police official Abdullah Khan said.

Government official Dilawar Khan Bangash said 41 people were killed and 62 were wounded in the attack.

Pakistan has been hit by near-daily explosions over the last 18 months blamed on Al Qaeda and Taliban militants. Most have been directed at security or government installations, but civilians have also been targeted, sometimes to punish those seen as cooperating with the government.

The food point was for people who fled from the Orakzai district, where the army has been fighting militants since the end of last year. The tempo of the operations has picked since March, with frequent aerial bombardment. The center provides food for up to 2,000 people.

There was no claim of responsibility, but that is not unusual when bomb attacks kill ordinary Pakistani citizens.

About 210,000 civilians have fled from Orakzai since the end of last year, including nearly 50,000 people who have left in the last month when ground forces moved into the area to flush out insurgents.

There have been fewer bombings in major cities outside of the northwest during the first three months of this year compared to late last year. The slowdown follows a major offensive in the South Waziristan tribal region, where many militants had been based.

The army's apology was for airstrikes in the Khyber region last Saturday that villagers said killed about 70 people.

The army spokesman had insisted the dead were militants, even when members of the local administration said they were compensating the families of dead civilians.

In a brief statement Saturday, army chief Gen. Ashfaq Parvez Kayani said he had ordered measures be taken to avoid such "unfortunate incidents" in the future. It mentioned the name of the tribe which lost members in the air strike.

The Pakistan army relies on the support -- or at least the neutrality of -- of tribes in the northwest to carry out its operations there.

Khanan Gul Khan, who lost four relatives in the attack, said he accepted the apology.

"The dead cannot come back, but we are happy that it has been acknowledged on the highest level that we are not terrorists," he said.

The Pakistani military regularly claims to have killed many militants in airstrikes, shellings and ground operations in the northwest, but rarely mentions civilian deaths. It is unclear whether few such deaths occur, or if the army simply does not report them.

Independent accounts of army operations in the tribal regions are extremely rare. Much of the area is still controlled by militants and is out of bounds for reporters.