Over 60 pro-Taliban militants and 20 soldiers were killed in fierce clashes between security forces and rebels in the troubled North Waziristan tribal region; where over 50 Pakistani troops were reported missing on Monday.

Military spokesman Major General Waheed Arshad said army authorities had lost contact with two groups comprising over 50 security personnel in an area south of Mirali town.

"There was some clash with the militants and the troops came under fire from the militants," Arshad told a private TV channel on Monday. "Then there was loss of contact. We are trying to locate these troops," he added.

Arshad sought to downplay the incident, saying clashes in the area between militants and troops were nothing new.

The clashes started on Sunday morning after the military launched an operation against the militants in retaliation for attacks on security forces by the rebels.

Fifteen soldiers and 35 militants were also injured in the clashes, the most severe since the pro-Taliban rebels scrapped a peace deal with the government in July. However, Taliban spokesman Ahmedullah Ahmadi denied any casualties among the militants.

Local residents said that the Army used fighter jets and gunship helicopters to bomb the mountainous region and alleged that several civilians were killed and injured in the attacks. TV channels said at least eight civilians, including three women and children, were killed in the clashes.

The army did not confirm reports of civilian casualties and Arshad said that security forces had launched attacks from places which were, "legitimate targets from where the army is attacked".

Arshad also said that a jirga or council of tribal elders was trying for a ceasefire to recover bodies from the rubble of destroyed buildings. Locals claimed that the army had imposed an undeclared curfew in the area and the main markets in Mirali and Miranshah had been closed down.