Afghanistan's Taliban rulers ordered all national and international NGOs to stop their women employees from working after "serious complaints" about their dress code, the Ministry of Economy said.
The order threatened to suspend the operating licences of NGOs that failed to implement the directive.
The EU strongly condemned the Taliban's ban on women working for NGOs in Afghanistan and said it was assessing the impact on its aid in the country.
Spokeswoman for EU foreign policy chief Josep Borrell told AFP in a statement: "We are assessing the situation and the impact it will have on our aid on the ground."
The EU is a major funder of aid organisations that work in Afghanistan. However it does not recognise the Taliban as the country's official government.
Mr Borrell's spokeswoman Nabila Massrali said: "Our foremost concern will continue to be the welfare, rights, and freedoms of the people of Afghanistan."
She said the ban on women working for NGOs "is another harsh restriction on the ability of women in Afghanistan to exercise their human rights and fundamental freedoms and a clear breach of humanitarian principles".
US Secretary of State Antony Blinken also warned that a Taliban order for women to be barred from working for NGOs would disrupt aid delivery and could be "devastating" for Afghanistan.
"Deeply concerned that the Taliban's ban on women delivering humanitarian aid in Afghanistan will disrupt vital and life-saving assistance to millions," Blinken tweeted.
"This decision could be devastating for the Afghan people."
While the Taliban had promised a softer form of rule when they returned to power in August last year, they have instead imposed harsh restrictions on women - effectively squeezing them out of public life.
"There have been serious complaints regarding the non-observance of the Islamic hijab and other rules and regulations pertaining to the work of females in national and international organisations," said a notification sent to all NGOs, a copy of which was obtained by AFP and confirmed by economy ministry spokesperson Abdulrahman Habib.
"The ministry of economy... instructs all organisations to stop females working until further notice," the notification said.
"In case of negligence of the above directive, the license of the organisation which has been issued by this ministry, will be cancelled," it added.
Two international NGOs confirmed that they had received the notification.
"We are suspending all our activities from Sunday," a top official at an international NGO involved in humanitarian work told AFP on condition of anonymity.
"We will soon have a meeting of top officials of all NGOs to decide how to handle this issue."
Dozens of national and international NGOs continue to work in several sectors across remote areas of Afghanistan, and many of their employees are women.
It was not immediately clear whether the order applied to United Nations (UN) agencies, which have a large presence in Afghanistan and often contracts with NGOs registered there to carry out its humanitarian work.
Mr Habib said the letter applied to organisations under Afghanistan's coordinating body for humanitarian organisations, known as ACBAR. That body does not include the UN, but includes over 180 local and international NGOs.
Aid workers say female workers are critical to ensuring women can access aid.
Blows to women's rights
The order is the latest assault on women's rights in Afghanistan.
Female university students were turned away from campuses this week and the higher education ministry said their access would be suspended "until further notice".
That ban was announced less than three months after thousands of women were allowed to sit university entrance exams.
Women have also been pushed out of government jobs.
Acting Higher Education Minister Nida Mohammad Nadim told Afghan state broadcaster RTA that several issues had prompted the decision, including female students not wearing appropriate Islamic attire and interaction between students of different genders taking place.
"They didn't observe Hijab, they were coming with the clothes that mostly women wear to go to a wedding," he said.
Calling on the Taliban to reverse the ban, US Secretary of State Antony Blinken said the Taliban were trying to sentence Afghanistan's women "to a dark future without opportunity" by barring them from attending universities.
In response to the order, around 400 male students boycotted an exam in the southern city of Kandahar - the de facto power centre of the Taliban - a rare protest staged by men.
The students' walkout was dispersed by Taliban forces who fired into the air, a lecturer at Mirwais Neeka University where the protest happened told AFP on condition of anonymity.
US-led forces withdrew from Afghanistan in August 2021 after 20 years of war as the Western-backed former government collapsed and the militants, who enforce a strict interpretation of Islam, seized Kabul.
On Thursday, the Group of Seven (G7) wealthy nations said gender persecution may amount to a crime against humanity, in a statement condemning the Taliban's decision on universities.
Mr Nadim said in his interview that the Taliban "asked the world not to interfere in our affairs", adding that discussions over female education were ongoing.
The Taliban had already barred teenage girls from secondary school, and women have been pushed out of many government jobs, prevented from travelling without a male relative and ordered to cover up outside of the home, ideally with a burqa.
They are also not allowed to enter parks or gardens.
The Taliban have also resumed public floggings of men and women in recent weeks, widening their implementation of an extreme interpretation of Islamic law.
