At least four people were killed and two others injured in a US drone strike launched in Pakistan 's northwest tribal area of North Waziristan on Tuesday night, reported local Urdu TV channel Dunya.

According to the report, the US drones fired two missiles at a house suspected of being a militants' hideout in the Tehsil Shawal area of North Waziristan at about 9:00 p.m. Tuesday, leaving at least four people inside the house killed and two others wounded.

Identities of the killed and injured are not immediately known.

Located in northwest Pakistan, North Waziristan is believed to be a haven of militants who often launch cross-border attacks on the US-led NATO troops stationed in Afghanistan.

As North Waziristan is a mountainous area difficult for ground operations, the United States has been using unmanned aircraft to attack the militants hiding in this area though such attacks have violated the territorial rights of Pakistan.

Drone strike has become one of the major factors affecting the US-Pakistan relationship. Despite the repeated protests by the Pakistani side, the United States has no intention to stop such strikes as it believes they are an effective way to fight against the militants hiding along the Pakistan-Afghanistan border areas.