PESHAWAR: At least 21 militants were killed in air strikes and ground operations that began overnight in Shawal area near the Pak-Afghan border, the military’s media wing claimed on Tuesday.

Military spokesman Asim Bajwa said the Pakistan Air Force (PAF) and Army Aviation's helicopter gunships carried out strikes in Shawal Valley of North Waziristan. The strikes began Monday night and continued into Tuesday, he said.

“Ops continue. Imp heights & passes along Pak-Afgn Bdr secured. Valley's sanitisation in progress,” he said on Twitter.

He later posted photographs of soldiers fanning out in a forested area and a ruined building engulfed in smoke.

This information could not be independently verified as journalists have limited access to the war-torn region.

Military operation Zarb-i-Azb was launched in North Waziristan on June 15, 2014, following a brazen militant attack on Karachi's international airport and the failure of peace talks between the government and Tehreek-i-Taliban Pakistan (TTP) negotiators.

According to official statements, over 3,500 militants have been killed in operation Zarb-i-Azb, while the offensive forced over a million civilians to vacate their homes and move to settled areas of the country.

Chief of Army Staff Gen Raheel Sharif ordered troops on Wednesday to march on the last bastion of terrorists in Shawal to take operation Zarb-i-Azb to its logical end.

North Waziristan is one of the seven regions in Pakistan's Federally Administered Tribal Areas (Fata) governed by tribal laws which is situated along the Pak-Afghan border.