Armed men stopped a special representative of U.N. Secretary General Ban Ki-moon in Ukraine's Crimea region on Wednesday, Ukraine's foreign ministry said.
U.N. Deputy Secretary General Jan Eliasson said Robert Serry had been threatened but had not been kidnapped.
Serry phoned up Ukraine's deputy foreign minister and described the incident as it was unfolding, Ukrainian Foreign Ministry Press Secretary Yevhen Perebiynis said.
"He said that as he left the headquarters of the navy in Simferopol, his vehicle was blocked by unknown men in uniform with weapons, who said they had an order to take him to the airport. He refused, and they are still holding him."
Crimea is under the control of Russian military forces, although Moscow describes its troops there who wear no insignia on their uniforms as "self-defence" units of the local administration.
