The Taliban’s lightning advance across Afghanistan has stirred fears they will reimpose their fundamentalist interpretation of Islam and all but eliminate women’s rights.

The blitz through the southern heartland means the Islamic militant group now holds half of Afghanistan’s 34 provincial capitals and controls more than two-thirds of the country.

Officials say the troops’ mission is just to assist the airlift of embassy personnel and Afghan allies, and they expect to complete it by month’s end, but troops might have to stay longer if the embassy is threatened by a Taliban takeover of Kabul.

The onslaught represents a stunning collapse of Afghan forces and renews questions about where the over $830 billion spent by the U.S. Defense Department went.

A U.S. peace envoy has brought a warning to the Taliban that any government that comes to power through force in Afghanistan won’t be recognized internationally.

The militant group has been surging for months in the country, taking swaths of land as U.S. and NATO forces complete their final pullout by the end of the month.

The spokesman for the Afghan Taliban says the insurgents will lay down their weapons when a negotiated government acceptable to all sides in the conflict is installed in Kabul and President Ashraf Ghani’s government is gone.