ISLAMABAD Pakistan said Friday NATO aircraft attacked one of its military posts in the northwest near the Afghan border and it had expressed its serious concern to the U.S. embassy in Islamabad.
The incident in the Mohmand tribal region comes after relations between the United States and its ally hit a new low following the killing of Osama bin Laden by U.S. SEALS in the Pakistani garrison town of Abbottabad in May.
The Pakistani Foreign Ministry said NATO aircraft intruded around 2.5 km (1.5 miles) inside Pakistani territory and attacked a military post.
Its statement said Pakistan had conveyed its "serious concern" to the U.S. embassy.
"A joint inquiry of the incident has also been requested," it said, without saying when did the incident took place.
Local officials in Mohmand said it occurred early Friday and that a few bombs were dropped but no casualties were reported.
Pakistan is crucial for the United States in its efforts to stabilize war-ravaged Afghanistan but relations have been seriously damaged since the killing of al Qaeda leader.
The United States kept Islamabad in the dark about the raid until after it was over, humiliating the Pakistani armed forces.
U.S. forces have also stepped up attacks on militant targets by remotely piloted drone aircraft in Pakistan's lawless tribal belt on the Afghan border -- dubbed the global hub of militants. Around 66 militants have been killed in such attacks this month.
Pakistan's army in return has drastically cut down the number of U.S. troops allowed in the country and set clear limits on intelligence sharing with the United States.
Pakistan army Friday rejected reports that its security forces tipped off insurgents at bomb-making factories after getting intelligence about the sites in its tribal areas from the United States.
"This assertion is totally false and malicious and the facts on ground are contrary to it," the military said in a statement.
The military said it had received information about four bomb-making factories in Waziristan -- the major sanctuary for al Qaeda and Taliban militants.
While two of them were destroyed, it said, the information about the other two was "incorrect." "Some persons have been arrested and they are under investigation."
Separately, Pakistan Friday summoned the Afghan ambassador in Islamabad to the Foreign Ministry and lodged a protest over a cross-border attack by "100-150 terrorists" on three border villages in Bajaur Thursday.
Pakistani officials in Bajaur said six civilians were killed in the attack, the second such cross-border incursion by militants reported by Pakistani officials this month.
(editing by Alison Williams)