ISLAMABAD (AFP) - Pakistan's military said Thursday it had killed 28 Taliban militants and lost five soldiers in the latest battles of a major offensive in the South Waziristan tribal area bordering Afghanistan.

Pakistan launched a fierce air and ground offensive into the northwest region on October 17, with 30,000 troops backed by fighter jets and helicopter gunships laying siege to Tehreek-e-Taliban bolt-holes.

"In last 24 hours, 28 terrorists have been killed, while five were apprehended. Security forces losses are five soldiers," the military said in a statement.

The soldiers were killed in a blast in the strategic town of Sararogha, a former operational base of late Taliban warlord Baitullah Mehsud, and 16 militants were killed in an ensuing gunbattle, it said.

Troops killed seven militants at villages between Taliban strongholds Shakai and Kanigurram in retaliation for a rocket attack, it added.

The military provides the only regular information coming from the frontlines. None of the details can be verified because communication lines are down and journalists and aid workers barred from the area.

In Islamabad, the United Nations urged Pakistan to ensure safety for civilians and aid workers during the ongoing offensive.

"We are very concerned that all who are involved in the military operations must take the absolute first priority to assure safety and security of the civilians," UN humanitarian coordinator Martin Mogwanja told reporters.

US-based Human Rights Watch last week said it had received reports of civilian deaths and the destruction of property during the operations.