Afghanistan’s Taliban-run administration has ordered all local and foreign non-governmental organisations (NGOs) to stop female employees from coming to work, according to a letter from the economy ministry.

The letter, the contents of which were confirmed by economy ministry spokesperson Abdulrahman Habib, said female employees of NGOs were not allowed to work until further notice.

It stated that the move was the result of some women allegedly not adhering to the administration’s interpretation of Islamic dress code for women.

Aid workers have said female personnel are critical to ensuring women can access support.

While ACBAR does not include the United Nations, it does include more than 180 local and international NGOs and the UN often contracts such groups registered in Afghanistan to carry out its humanitarian work.

Quite how this order will affect UN agencies, which have a large presence in Afghanistan delivering services amid the country’s humanitarian crisis, is not clear.

It was also unclear whether the rule also applied to foreign women.

Dozens of organisations operate across remote areas of Afghanistan and many of their employees are women, with several warning a ban on women staff would hinder their work.

The International Rescue Committee said in a statement its more than 3,000 women staff in Afghanistan were “critical for the delivery of humanitarian assistance” in the country.

An official at an international NGO involved in food distribution said the ban was a “big blow”.

“We have women staff largely to address humanitarian aid concerns of Afghan women,” the official said. “How do we address their concerns now?”

US secretary of state Antony Blinken said women were “central to humanitarian operations around the world” and that the ban would be “devastating” to Afghans as it would “disrupt vital and life-saving assistance to millions”.

This latest attack on women’s rights and freedoms comes days after the administration ordered universities to close to women.

The move prompted international condemnation. This week foreign ministers from the G7 called on the Taliban to lift the ban, warning that “gender persecution may amount to a crime against humanity”.

However, the Afghan minister of higher education defended the ban. Nida Mohammad Nadim said the it would prevent men and women mixing at universities and he believed some subjects being taught violated the principles of Islam.

“We told girls to have proper hijab but they didn’t and they wore dresses like they are going to a wedding ceremony,” he said. “Girls were studying agriculture and engineering, but this didn’t match Afghan culture. Girls should learn, but not in areas that go against Islam and Afghan honour.”

He said universities would reopen for women once these issues, which he said were being worked on, were resolved.

However, this echoes the Taliban’s promises about secondary school access for girls, which was banned last year.

It had insisted classes would resume for girls once “technical issues” concerning uniforms and transport were sorted out. However the ban remains in place.

The Taliban has also banned girls and all female staff including teachers from primary schools meaning there is now in effect a total ban on education for women in the country.

Agence France-Presse contributed to this report