Pakistan's military says troops are closing in on a key Taliban-held town in the northwest, as the United Nations confirmed more than a million people have been displaced in two weeks of fighting.

Army spokesman Major General Athar Abbas said Saturday that security forces were approaching Mingora, the main town in Swat Valley, in an effort to intercept militants trying to flee the area.

The U.N. refugee agency says more than a million people have fled the area, since the military launched its offensive to stop Taliban militants who violated a peace deal and advanced to within 100 kilometers from the capital.

U.N. High Commissioner for Refugees Antonio Guterres on Saturday called for massive support, including millions of dollars, to help the displaced.

Elsewhere in Pakistan's northwest, a car bomb exploded in the city of Peshawar, killing at least 11 people, including children. 

Several others were injured in Saturday's blast that also hit a passing school bus.

Some information for this report was provided by AFP, AP and Reuters.