UNITED NATIONS, April 28 (Reuters) - U.N. Secretary-General Ban Ki-moon on Monday condemned the recent seizure in Ukraine of observers from the Organization for Security and Cooperation in Europe (OSCE) and demanded that pro-Russian rebels release them immediately.
"The Secretary-General strongly condemns the recent capture and detention of OSCE military monitors as well as a number of accompanying Ukrainian staff," the statement said. "He urges those responsible for their abduction to release them immediately, unconditionally and unharmed."
"He appeals to all those with influence to assist in the urgent resolution of this matter," the statement added.
Ban said international missions working in Ukraine must be allowed to perform their duties without interference, it noted.
"The Secretary-General urges all parties concerned to take immediate steps to de-escalate the situation in Ukraine," the U.N. statement said. "A diplomatic and political solution to this crisis is imperative and long overdue."
The OSCE monitors were detained last week by pro-Russian separatists in eastern Ukraine.
The captives - from Germany, the Czech Republic, Denmark, Poland and Sweden - were paraded before reporters on Sunday and said they were in good health. A Swede was freed for medical reasons but the others are still being held, described by the rebel leader as "prisoners of war" and NATO spies. (Reporting By Louis Charbonneau; Editing by Meredith Mazzilli)