ISLAMABAD, Oct. 1 (Xinhua) -- A missile strike by a suspected United States spy drone killed at least four people in Pakistan's tribal area, private TV channel Geo reported Wednesday.

    The missile hit a house in a Pakistani tribal area bordering Afghanistan, killing at least four people and injuring nine others, security officials said.

    The incident took place shortly after some tribesmen shot at three drones circling the village of Khusali Toorikhel in North Waziristan tribal area, according to Geo.

    "After the drones came under fire a missile hit a house in the village," the Geo quoted a local security official as saying.

    The U.S. State Department recently reaffirmed its respect for Pakistan's sovereignty and territorial integrity amid concern voiced by Pakistani leadership and government about the cross-border raids launched by U.S. and coalition forces based in Afghanistan.