A major rebel group in Sudan's strife-torn Darfur region said on Monday it had captured 49 international peacekeepers, most of them from Senegal, and accused them of cooperating with the country's security service.
All soldiers were later freed, the rebels said.
The joint UN-African Union UNAMID peacekeeping force has been repeatedly caught in the crossfire during almost 10 years of fighting between government troops and insurgents in Sudan's remote west.
The capture of more than 50 soldiers will be seen as a major setback for an already stretched mission, set up to keep the peace in a territory the size of France.
"We are holding the UNAMID soldiers because they entered our territory without permission and because they were accompanied by three Sudanese we suspect work for the security services," Gibreel Adam Bilal, a spokesman for the rebel Justice and Equality Movement (JEM) told Reuters earlier.
He said JEM suspected UNAMID of helping Sudan's security services to spy on territory held by the rebel group.
"If it is true that UNAMID works with Sudan security agents, then we will ask the UN to fire the head of the UNAMID force," he said, adding JEM was also holding peacekeepers from Yemen and Ghana.
Susan Manuel, a spokeswoman for the African Union-UNpeacekeepers declined to comment earlier, saying only: "There is a situation on the ground unfolding since yesterday which we're trying to resolve."