KABUL, Afghanistan -- Dozens of people were stopped from "illegally" leaving Afghanistan by air on Monday, a top Taliban official said, and several women among them are being detained until they are collected by male relatives.

Tens of thousands of Afghans fled on evacuation flights from Kabul in August as the Taliban returned to power amid the hasty withdrawal of US-led forces.

Some nations and international NGOs have since operated irregular chartered flights extracting Afghans, but Taliban authorities have increasingly clamped down.

Taliban spokesman Zabihullah Mujahid tweeted late Monday that a group had attempted to leave on a flight from the northern city of Mazar-i-Sharif.

"Forty people were arrested... who wanted to go abroad illegally by plane," he said.

He said most were released, but some women "remain detained because their male relatives have not yet come to escort them".

It was not immediately clear who had organised the flight.

Tens of thousands Afghans are still desperate to leave the country -- fearful of reprisals from the Taliban because of their links to foreign forces or the former US-backed regime.

The Taliban insist anyone can leave as long as they have the right documents -- including visas to wherever they are going -- but getting the paperwork in a country where only a handful of embassies operate is extremely difficult.

The hardline Islamist government has also called on Afghans with skills and training to stay and help rebuild the country.

Despite promising a softer version of rule compared to their first stint in power from 1996 to 2001, the Taliban have imposed several restrictions on women.

They are barred from long-distance travel unless accompanied by a close male relative, and have also been stopped from returning to work in most government sectors.

In recent weeks women activists have staged small and sporadic protests in Kabul and other cities, but the rallies are usually forcefully dispersed.