Burkina Faso's military government says it has arrested eight people working for a humanitarian organization, accusing them of "spying and treason", allegations the Dutch nonprofit "categorically" rejected.

Burkina Faso's Security Minister Mahamadou Sana said the eight people arrested worked for the International NGO Safety Organization (INSO), a Netherlands-based group specializing in humanitarian safety.

Those detained included a French man, a French-Senegalese woman, a Czech man, a Malian and four Burkinabe nationals, Sana said, alleging the staff members had continued working for the organization after it was banned for three months, for allegedly "collecting sensitive data without authorization".

The security minister claimed some of INSO's staff had "continued to clandestinely or covertly conduct activities such as information collection and meetings in person or online" following the ban, including its country director, who had also previously been arrested when the suspension came into effect at the end of July.

Sana said the INSO staff members had "collected and passed on sensitive security information that could be detrimental to national security and the interests of Burkina Faso, to foreign powers".