Islamabad, Sep 14 (IANS): At least three security men were killed in a militant attack in the restive North Waziristan tribal region in Pakistan Sunday, a media report said.

Official sources said that scores of rockets were fired at the Spinwam Security Fort on the Pakistan-Afghanistan border, killing three Pakistani soldiers and injuring two others, Dawn online reported.

The military operation 'Zarb-i-Azb' was launched by the Pakistan Army June 15 following a brazen militant attack on Karachi's international airport and failure of peace talks between the government and Tehreek-i-Taliban Pakistan (TTP) negotiators.

Expressing sorrow over the incident, Prime Minister Nawaz Sharif said the sacrifices of the armed forces for security of the country would not go in vain.

The premier also extended condolences to the families of the slain soldiers.

On Wednesday, at least 65 militants were killed in airstrikes carried out by the Pakistan Army in the country's north-western tribal area.

Earlier in the month, a statement issued by the military put the official number of terrorists killed in operation at 910 and the number of Pakistani soldiers who had lost their lives during the offensive at 82.

Inter Services Public Relations, the mouthpiece of the Pakistan Army, is yet to issue an official statement on the attack.