Internally displaced Afghans from northern provinces, who fled their home due to fighting between the Taliban and Afghan security personnel, wait to receive free food in a public park in Kabul, Afghanistan, Tuesday, Aug. 10, 2021.

KABUL, Afghanistan — A U.S. peace envoy brought a warning to the Taliban on Tuesday that any government that comes to power through force in Afghanistan won't be recognized internationally after a series of cities fell to the insurgent group in stunningly quick succession.

Zalmay Khalilzad, the U.S. envoy, traveled to Doha, Qatar, where the Taliban maintain a political office, to tell the group that there was no point in pursuing victory on the battlefield because a military takeover of the capital of Kabul would guarantee they would be global pariahs. He and others hope to persuade Taliban leaders to return to peace talks with the Afghan government as American and NATO forces finish their pullout from the country.

The insurgents have captured six out of 34 provincial capitals in the country in less than a week, including Kunduz in Kunduz province — one of the country's largest cities. On Sunday, they planted their flag in the main square, but government forces still controlled the strategic airport and an army base on the city's outskirts.

They are now battling the Western-backed government for control of several others. Late on Tuesday, Taliban forces entered Farah and were seen in front to the provincial governor's office.

Taliban spokesman Zabihullah Mujahed tweeted the insurgents had taken the city, which is the capital of a province with the same name. But Abdul Naser Farahi — a lawmaker from the area who is in Kabul — said the government still retained control of the intelligence department and a military base.

After a 20-year Western military mission and billions of dollars spent training and shoring up Afghan forces, many are at odds to explain why the regular forces have collapsed, fleeing the battle sometimes by the hundreds. The fighting has fallen largely to small groups of elite forces and the Afghan air force.

The success of the Taliban blitz has added urgency to the need to restart the long-stalled talks that could end the fighting and move Afghanistan toward an inclusive interim administration. The insurgents have so far refused to return to the negotiating table.

Khalilzad's mission in Qatar is to “help formulate a joint international response to the rapidly deteriorating situation in Afghanistan,” according to the U.S. State Department.

He plans to “press the Taliban to stop their military offensive and to negotiate a political settlement, which is the only path to stability and development in Afghanistan,” the State Department said.

By Associated Press