Pakistani officials say at least five people have been killed in a suspected U.S. missile strike along the Afghan border.

Security officials say the strike occurred Friday in the Gurwak village of the North Waziristan tribal area.  While some officials said those killed were suspected militants, others said that civilians were killed - including women and children.

Witnesses said they saw drone (unmanned) aircraft flying above the village before the attack.  Pakistan army spokesman Major General Athar Abbas said he had received reports of the blast.

On Thursday, Pakistani officials said another suspected drone missile strike had hit a home in North Waziristan's Mohammad Khel area, killing four militants.

It was not immediately clear who was responsible for both blasts.  But the United States has used drones to target militants along Pakistan's border with Afghanistan in the past.

Pakistan's foreign minister formally complained to the United States about a suspected U.S. attack on another target near the Afghan border.

Details about that raid, which took place Wednesday in a village in South Waziristan, are still not clear.  U.S. military sources, speaking on condition of anonymity, told Western media that American troops based in Afghanistan carried out the operation.

Pakistani officials say at least 20 people, including women and children, were killed in the pre-dawn assault involving helicopter gunships and ground troops. 

The White House has declined to comment on the incident, but today the White House press secretary, Dana Perino, said the United States respects Pakistan's sovereignty and is working with the new government to fight terrorism.

Violence has been on the rise for months in eastern Afghanistan.  U.S. commanders say safe havens in Pakistani tribal areas have given militants space to re-arm and plan attacks.

Some information for this report was provided by AFP, AP and Reuters.