KACHA PUKA, Pakistan (AP) — Two burqa-clad suicide bombers attacked refugees from a Pakistani offensive against the Taliban, killing 41 as they lined up to register for food and other relief supplies.

The victims were among around 200,000 people to have left the Orakzai region along the Afghan border since the end of last year, when the Pakistan army began offensive ground and air operations against militants based in the remote, tribally administered region.

The registration point in Kohat region was managed by the local administration, but sometimes used by foreign humanitarian groups, including the World Food Program, to deliver aid. There was no claim of responsibility for Saturday's bombings, which is not unusual when ordinary Pakistanis are killed.

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

Al-Qaida and Taliban militants based in the northwest have carried out near-daily attacks over the last 18 months in Pakistan, seeking to overthrow its Western-allied government and stop it from fighting them. The blasts have killed several thousand people, but not deterred the army.

Most of the attacks are directed at security or government installations, but civilian targets have also been hit.

The registration point — essentially a small building in a dusty field — may have been hit to persuade people not to have any contact with the local administration or foreign relief groups.

The bombers were disguised in burqas, the all-encompassing veil worn by conservative Muslim women in parts of Afghanistan and Pakistan, allowing them to get close to the building without arousing suspicion, said police officer Abdullah Khan.

They struck within minutes of each other, with the second blast the bigger and more deadly.

An Associated Press photographer at the distribution point in Kacha Puka saw pools of blood, body parts and caps and shoes littering the dusty floor.

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

The tempo of the operations in Orakzai has picked up since March, with frequent aerial bombardment. Nearly 50,000 people have left in the last month.

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

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 — something that could help reduce anger among local tribes, whose support it needs to defeat the militants.

In a brief statement, 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.

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.