PESHAWAR: At least four suspected militants were killed when a US drone fired two missiles at a hideout in South Waziristan tribal region's Shawal area along the Pak-Afghan border on Sunday.

South Waziristan is among Pakistan’s seven tribal districts near the Afghan border which are rife with homegrown insurgents and are alleged to be strongholds of Taliban and Al Qaeda operatives, among others.

Also read: Drone strike near Khyber border kills nine, including driver of LI chief

According to sources, the four killed belonged to the 'Sajna' group of the outlawed Tehreek-i-Taliban Pakistan (TTP).

The airstrikes come amid the ongoing Khyber- 1 and Khyber- 2 operations launched by the military in Khyber tribal region and are part of the military's stepped-up efforts since a militant attack in December killed 150 people, mostly children, at an army-run school in Peshawar.

Take a look: Drone strike near Pak-Afghan border takes out Hakimullah's aide

Military operation Zarb-i-Azb was launched by the Pakistan Army on 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.