ISLAMABAD, Pakistan  Two missiles fired from an American drone aircraft killed at least six militants in North Waziristan on Sunday, Pakistani security officials said.

American drone attacks have recently increased in the region, on the border with Afghanistan, which is the main hub of Al Qaeda and the Afghan Taliban faction led by Sirajuddin Haqqani, whose fighters are involved in attacks against NATO and American forces in Afghanistan.

The target of the attack on Sunday was a compound in the town of Mir Ali. The identity of those killed was not clear.

The Pakistani military is currently involved in an offensive in South Waziristan, the base of the Pakistani Taliban, but is under increasing pressure from the United States to expand the offensive to North Waziristan.