A suspected U.S. drone strike has killed four people in Pakistan's North Waziristan tribal region.

Pakistani officials and local media say that two missiles from an un-manned American aircraft struck a compound and a vehicle parked outside it early Tuesday in the town of Miran Shah.

Officials say at least four suspected militants were killed and another two wounded.

Miran Shah, located along the border with Afghanistan, is the main town in the semi-autonomous North Waziristan tribal district, a known refuge for al-Qaida and Taliban linked militants.

Last Wednesday, a similar strike killed at least 21 suspected militants in a compound near Miran Shah.

U.S. officials do not publicly acknowledge the use of drone strikes inside Pakistan, but privately have confirmed their existence to various news outlets.

Separately, Pakistani officials say unidentified gunmen set fire to at least seven tankers carrying fuel for foreign troops in neighboring Afghanistan.

The officials said that an explosion at a terminal at the Torkham border crossing in the northwest destroyed at least three tankers. Minutes later, in the same area, two more NATO tankers were damaged when the gunmen fired at them.

After a separate attack near the central Pakistani city of Multan, four oil tankers were burning late Monday.

Last week, the Pakistan Oil Tankers Owners Association demanded more protection from the government. The group threatened Friday to stop supplying NATO within 24 hours if the government fails to act.

The bulk of fuel and other non-lethal supplies for NATO troops in Afghanistan moves through Pakistan.