Pakistani security officials say two missiles fired by a suspected U.S. drone hit a militant compound in the tribal region near the Afghan border late Sunday, killing as many as 20 people.

The officials say the compound is located in South Waziristan - a stronghold of Pakistan's top Taliban commander, Baitullah Mehsud. There was no immediate confirmation on the strike from the United States.

A similar air strike last Thursday in North Waziristan on a religious school - belonging to a cleric linked to Taliban commander Jalaluddin Haqqani - killed at least 11 people.

Earlier Sunday, 10 militants, including three commanders, and at least five pro-government tribal fighters, were killed in a gunbattle in Northwest Frontier Province.

Officials say the clash erupted after militants kidnapped about 70 people in Swat valley and killed at least eight of them.

In the nearby Bajaur tribal region, Pakistani government forces backed by helicopters killed at least eight militants.

Bajaur is a mountainous tribal area where Taliban and al-Qaida militants regularly launch cross-border raids into neighboring Afghanistan

In other violence Sunday, a suicide bomber rammed his explosives-laden car into a security checkpoint in the Mohmand tribal area near Bajaur, killing at least 10 people and wounding at least five others. Most of the victims were security personnel.

And, police said the brother of Pakistani Taliban chief Baitullah Mehsud was shot dead in Northwest Frontier Province. The motive for his murder was not clear, since he was not involved in Taliban activities.

The military says its two-month-long offensive in Bajaur has claimed the lives of nearly 1,500 suspected militants and 73 troops.

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