Four Organization for Security and Cooperation of Europe (OSCE) monitors have been captured by insurgents in eastern Ukraine, the Ukrainian foreign ministry said Wednesday.
"They are detained by pro-Russian groups and we are working to release them," Xinhua quoted Foreign Ministry spokesman Eugene Perebiynis as saying.
Ukrainian law enforcement agencies had sent a special unit to free the captives as soon as possible, Perebiynis said, adding their whereabouts were not yet known.
On Tuesday, the OSCE said it had lost contact with a four-person monitoring team, which was on an observing mission near Ukraine's Donetsk.
The team is comprised of a Turk, an Estonian, a Dane and a Swiss.
Earlier in the day, German OSCE special envoy Wolfgang Ischinger said the organization could withdraw its monitors if their lives were at risk.
In April, rebels took a group of OSCE military observers, mostly from Europe, in Donetsk region and held them for a week.
