Pakistani intelligence officials say a U.S. drone strike has killed at least four suspected militants in the country's tribal region.

Monday's attack took place in the South Waziristan tribal region.

The area is a known stronghold for Pakistani Taliban and al-Qaida-linked militants and has been repeatedly targeted by missiles fired from pilotless aircraft in recent months.

The United States does not publicly acknowledge the drone strikes, which Pakistan has criticized as a violation of its sovereignty.

On Monday, a senior commander of the Pakistani Taliban said he was splitting from the group to protest attacks against “innocent” civilians.

Fazal Saeed told reporters he had been serving as the leader of the Tehrik-e-Taliban in the Kurram tribal agency.

Saeed said he has repeatedly told leaders of the militant group that suicide bombings against mosques and other civilian targets must be stopped.

Thousands of civilians and police have been killed in such attacks claimed by the Taliban.

A Taliban militant and his wife reportedly carried out Saturday's attack on a police station in the northwestern town of Kolachi, killing at least 10 police officers.