A US missile strike destroyed a house in a North Waziristan village today, killing at least 21 people according to a senior Pakistani official. Of the 21, a local official said 16 of them foreigners. He also added that the house belonged to two Afghan refugees who settled in the area after the 2001 US invasion.

Another report claimed that a separate US air strike in a different village early in the morning killed three civilians and injured at least six others. This report was denied by Pakistani military spokesman Major General Athar Abbas, who told the AFP that this second strike was actually on the Afghan side of the border, not on Pakistani soil. He said the US informed the Pakistani government before the Afghan strike, but so far there has been no official military comment regarding the much larger North Waziristan strike.

This is the second US air strike on North Waziristan this week, with a previous attack killing at least nine and injuring several others. The US has been escalating its unilateral attacks on Pakistani soil over the past month, damaging relations between the Bush Administration and the fledgling government of President Asif Ali Zardari. Pakistani forces have been reported to open fire on US incursions several times in recent weeks, with the most recent conflict leading to a reported five minute firefight between US and Pakistani ground troops. Pakistani Prime Minister Yousef Raza Gilani has said the US strikes are a “form of terrorism” and must stop.