ISLAMABAD - Reacting strongly to the US-led coalition troops' attack on Angoor Adda, South Waziristan, Pakistan Wednesday summoned the American Ambassador to the Foreign Office to lodge protest. The US envoy Anne W Patterson was received by the Additional Secretary, America Division (Foreign Office), Attiya Mahmood, who told her that the attack was gross violation of Pakistan's territory. The Additional Secretary lodged a strong protest on the occasion with a warning to Washington to refrain from such acts in future, said a senior official requesting anonymity. The US diplomat was told that such attacks on Pakistani soil were unacceptable, he added. The Foreign Office Spokesman, Muhammad Sadiq, when approached, also confirmed that the US envoy was summoned to Foreign Office Wednesday evening. In his reaction, he said that Pakistan strongly condemned the assault by US- led coalition troops, also called ISAF, at a village near Angoor Adda inside Pakistani territory, which has resulted in immense loss of civilian lives. "This helicopter borne ground attack, supported by air assets based in Afghanistan, is gross violation of Pakistan's territory," he said. "It is, indeed, most unfortunate that Coalition/ISAF in Afghanistan have resorted to cross-border use of force against civilians. Such actions are counter-productive and certainly don't help our joint efforts to fight terrorism," Sadiq said. On the contrary, he said such acts undermined the very basis of cooperation and might fuel the fire of hatred and violence that Islamabad was trying to extinguish. "Moreover, any attack on Pakistani territory is unacceptable and constitutes a grave provocation," he said.