Pakistan has blamed US-led coalition forces in Afghanistan for a "cowardly" air raid which killed at least 10 Pakistani soldiers at a border post.
The alleged attack on Wednesday came after Pakistani paramilitary troops in the Mohmand tribal area clashed with Afghan forces in an area fought over by the two countries, Pakistani officials said.
"The spokesman condemned this completely unprovoked and cowardly act on the FC [Frontier Corps] post and regretted the loss of precious lives of our soldiers," a Pakistani military statement said.
"A strong protest has been launched by the Pakistan army and we reserve the right to protect our citizens and soldiers against aggression."
The US and Afghan military have not yet responded to the allegations.
Damagh Khan Mohmand, a local tribesman who witnessed the outbreak of fighting late on Tuesday, said the clashes lasted for four hours.
He said Afghan and foreign forces traded fire with both Pakistani tribesmen and troops.
Two aircraft then bombed several locations, hitting two Frontier Corps posts, Khan Mohmand said.
Ten Pakistani paramilitary troops died in the exchange of fire and air raid, a military official in northwestern Pakistan said.
Hyder said the incident is not the first attack on a Pakistani military post.
"A little over a month ago there was an attack at a post not far from Chopara checkpoint," he said.
"Al Jazeera sources in Kabul say that the Nato-led coalition is investigating. The coalition has not released any official statements; nor has the Pakistani military.
"There has been anger from the tribal groups, who have an armed group. They are now saying they will retaliate across the border for the strike."
Pakistan's new government entered peace talks with Taliban loyalists shortly after allies of Pervez Musharraf, Pakistan's president, were beaten in recent elections.
Güncelleme Tarihi: 12 Haziran 2008, 12:23