Armed militants stormed a university in volatile northwestern Pakistan, killing at least 20 people and wounding dozens a little more than a year after the massacre of 134 students at a school in the area, officials said.

The Taliban massacre that killed 148 people, mostly children, at a military-run school in north-western Pakistan left a scene of heart-wrenching devastation, pools of blood and young lives snuffed out as the nation mourned and mass funerals for the victims got under way.

Taliban gunmen stormed a military-run school in the north-western Pakistani city of Peshawar, killing at least 141 people, mostly children, before Pakistani officials declared a military operation to clear the school over.

The death toll in a Taliban attack on a school in the city of Peshawar in Pakistan has risen to 126, an official says.