°®Âþµº

The US negotiator on Afghanistan, Zalmay Khalilzad, "will press the Taliban to stop their military offensive" at talks in Doha this week, the State Department said Monday after the insurgents seized a series of provincial capitals.

"Ambassador Khalilzad will be in Doha to help formulate a joint international response to the rapidly deteriorating situation in Afghanistan," the department added in a statement.

Fighting in long-running conflict has escalated dramatically since May, when the US-led military coalition began the final stage of a withdrawal set to be completed before the end of the month.

"The increased tempo of Taliban engagement, resulting civilian causalities in armed conflict between the sides, and alleged human rights atrocities are of grave concern," the US statement said.

"A negotiated peace is the only path to ending the war."

The Taliban seized a sixth Afghan provincial capital on Monday following a weekend blitz that saw urban centers fall in quick succession and the government struggle to keep the militants at bay.

The insurgents say they are moving in on Mazar-i-Sharif -- the largest city in the north and a linchpin for the government's control of the region.