KABUL, Afghanistan (AP) — The Taliban have detained 18 staffers, including a foreigner, from a nongovernmental organization based in Afghanistan, the nonprofit group said Friday.

NGOs have come under greater scrutiny since the Taliban seized control of the country two years ago. Following the takeover, the Taliban introduced harsh measures and barred Afghan women from education beyond the sixth grade, as well as from public life and work, including from working for NGOs. A U.S. watchdog reported earlier this year that the Taliban are harassing NGOs operating in the country.

The International Assistance Mission said 18 of its staff were taken away by the Taliban on two separate occasions this month from the NGO’s office in central Ghor province. The 18 detained have been taken to Kabul, the mission said.

“We are unaware of the circumstances that led to these incidents and have not been advised of the reason for the detention of our staff members,” it said in a statement. “The well-being and security of our colleagues are paramount to us, and we are doing everything possible to ensure their safety and secure their swift release.”

Afghan officials were not immediately available for comment.

Local media, quoting the provincial governor’s spokesperson, Abdul Wahid Hamas, said the foreigner is a U.S. national and that the staff were detained for “propagating and promoting Christianity.”

The reports did not identify the alleged American staffer and there was no immediate comment from Washington. The NGO did not immediately respond to questions from The Associated Press about the reports.

The nonprofit, which is registered in Switzerland, says it only works in Afghanistan.