Pakistani security forces killed 30 to 40 militants, and injured 10 to 12 others in the country's northwest tribal region bordering Afghanistan on Wednesday, an army spokesman said.

Pakistani military spokesman Major General Waheed Arshad told private Geo and DAWN NEWS TV channels that gunship helicopters were used to target positions of militants in mountains in the border area between North and South Waziristan.

The operation starting from the morning continued to the afternoon, he said, adding that the militants had been using mountains to fire and ambush convoys of security forces.

Talking to Geo earlier, Arshad said no ground forces and only gunship helicopters were used to hit suspected positions of the militants.

He said ground forces would soon be sent to the area to assess casualties of the militants.

There had been no losses of the security forces, the spokesman said.

Violence has increased in Pakistan's tribal regions since July when the military stormed Islamabad-based hard-line Red Mosque and armed tribals in North Waziristan scrapped a peace deal with the government.

Bombing attacks on security forces have been intensified against security personnel in Pakistan's northwest frontier over the two months, and over 300 people have been killed in various violence.

Earlier on Wednesday, Arshad confirmed that around 18 police personnel were reported missing following a Tuesday night militants' attack on a security checkpost in Bannu, a town neighboring North Waziristan.

Kidnappings of security men have increased in Pakistan's troubled tribal region since last month.

Around 260 soldiers kidnapped by local militants on August 30 in South Waziristan reportedly were still in militants' custody.

(Xinhua News Agency September 13, 2007)