The helicopters targeted the check post at Baizai area of Mohmand tribal region last night, officials were quoted as saying by TV news channels.
A brief statement from the Inter-Services Public Relations said International Security Assistance Force and Nato helicopters "carried out unprovoked and indiscriminate firing" on a Pakistani check post in Mohmand Agency. The Pakistani military said it did not have "confirmed details of casualties".Security forces blocked all entry points to Mohmand Agency after the incident and conducting the checking of all vehicles.
A spokesman for the Nato-led ISAF in Kabul said the coalition was aware of "an incident" near the border and was gathering information on it.
The incident occurred just a day after Pakistan Army chief Gen Ashfaq Parvez Kayani and the commander of coalition forces in Afghanistan, Gen John Allen, met in Islamabad and discussed the need for tighter measures to block the movement of militants across the Pakistan-Afghanistan border.
Kayani and Allen "discussed measures concerning coordination, communication and procedures between Pakistan Army, ISAF and Afghan Army aimed at enhancing border control on both sides", an army statement said.