U.S. drone attack inside Pakistan kills six villagers.

A suspected U.S. aerial drone fired missiles at a Pakistani tribal village in North Waziristan, killing six and wounding at least four people, an Afghan news agency reported Friday.

Pajhwok news agency said at least two drones were spotted in the area and one of them fired three missiles at the village, which straddles the Pakistan-Afghanistan border.

U.S.-led forces stationed in Afghanistan have recently stepped up operations against suspected al-Qaeda terrorists hiding in mountainous areas along the border between Afghanistan and Pakistan.

On Wednesday, U.S. troops conducted a ground assault on the village of Angor Adda in

South Waziristan preceded by a drone-launched missile strike. According to Pakistani officials the attack killed at least 20 people, including women and children.

Pakistani Foreign Minister Shah Mehmood Qureshi said Thursday that the Angor Adda attack was a shameful violation of the rules of engagement agreed with U.S.-led forces in Afghanistan.

North and South Waziristan, which both border Afghanistan, are virtual no-go areas for Pakistani government forces. The mountainous region is the stronghold of fiercely independent Pashtun tribes and is believed to be a safe haven for hundreds of Taliban fighters from Afghanistan blamed for the recent intensification of terrorist attacks in Pakistan and Afghanistan.