A senior Afghan official said President Ashraf Ghani was at the U.S. Embassy to consult with the U.S. envoy. Both the U.S. and Afghan government have asked the Taliban to hold off for two weeks until a transitional government could be agreed to, he said. “I do not think the Taliban will accept the offer,” he said.

Sporadic gunfire erupted in central Kabul in the late morning as the administration of Mr. Ghani told all employees to go home. Soon after, checkpoints were abandoned as panicked residents clogged the streets. By early afternoon, the Taliban took over Kabul’s main Pul-e-Charkhi prison, freeing thousands of inmates, videos on social media showed.

At the U.S. Embassy on Sunday afternoon, helicopters ferried American and Western diplomats and civilians to the military side of Kabul airport. One after another, Chinooks and Black Hawks took off from the landing zone, spraying dust.

Below them was a city of traffic jams and roundabouts choked by cars—many of them filled with Afghans trying to reach the airport’s relative safety. Dark smoke, presumably from burning documents, rose from the presidential palace.