The Pakistani military says its troops have killed at least a dozen militants in the ongoing offensive targeting pro-Taliban militants based in South Waziristan.

"In the last 24 hours, 12 terrorists have been killed, and five soldiers, including two officers, were injured," a Pakistani army statement said on Saturday.

Earlier on Friday, Pakistani military sources said soldiers had penetrated into the strategic town of Makin, an important base for the militants and the "operational center" of the banned Tehrik-e-Taliban Pakistan (TTP).

Over 450 militants and about 42 soldiers have been killed since the operation was launched in the mountainous terrain of Pakistan's Federally Administered Tribal Areas on October 17.

Meanwhile, in a separate incident on Saturday, police say two women teachers and some students were injured when a grenade was thrown into a girls' school in the southwestern city of Quetta, the capital of Balochistan Province.

JR/SS/HGL