More than 18,000 people have been flown out of Kabul since the Taliban took over Afghanistan's capital, a NATO official said on Friday, pledging to redouble evacuation efforts as criticism of the West's handling of the crisis mounted, Reuters reported.

Thousands of people, desperate to flee the country, were still thronging the airport, the official who declined to be identified said, even though the Taliban have urged people without legal travel documents to go home.

The Taliban urged unity ahead of Friday prayers, the first since they seized power, calling on imams to persuade people not to leave Afghanistan amid the chaos at the airport, protests, and reports of violence.