Two days after NATO forces conducted air strikes against militants within its territory, Pakistan on Monday protested against such attacks, saying they were "unacceptable" and a violation of its sovereignty.
Two air strikes by NATO and International Security Assistance Force helicopters on Friday and Saturday killed over 50 pro-Taliban militants on the Pakistani side of the border.
An ISAF statement issued on Monday confirmed the attacks, saying they were carried out after the helicopters came under fire from militants on the Pakistani side of the frontier.
US officials said they have an agreement which allows aircraft to cross a few kilometres into Pakistani airspace if they are in hot pursuit but Pakistan denied such a pact exists.
"Pakistan has strongly protested to ISAF/NATO on the two incidents of aerial engagements from the Afghanistan side into Pakistani territory by ISAF/NATO helicopters."
"These incidents are a clear violation and breach of the UN mandate under which ISAF operates," said a statement issued by Pakistan's Foreign Office.
The Foreign Office said Pakistan will have to consider "response options" if "immediate corrective measures" are not implemented.
A demarche was also relayed to NATO headquarters in Brussels. The UN mandate "terminates (or) finishes" at the Afghan border and there are "no agreed hot pursuit" rules, the statement said.
"Any impression to the contrary is not factually correct. Such violations are unacceptable," it added. The Foreign Office said ISAF and NATO forces had "been asked not to participate in any military action that violates the UN mandate and infringes upon Pakistans sovereignty".
Pakistan has always emphasized the need for "coordinated and joint action" against militant forces, the statement said. "Pakistan has boldly and at a great cost countered terrorists.
Element of trust followed by capacity enhancement of Pakistan's armed forces was stressed," it said. NATO justified the air strikes on the basis of "the right of self-defence".
The first attack took place after insurgents based in Pakistan attacked an Afghan outpost in Khost province, located across the border from Pakistan's North Waziristan tribal area.
