An insurgent leader is quoted as saying by the Interfax news agency that his fighters are holding four observers from the Organization for Security and Cooperation in Europe.
Vyacheslav Ponomarev, the self-proclaimed "people's mayor" of Slovyansk, a city in the Donetsk region, said Thursday that the four monitors are safe and promised that they would be freed soon. He didn't put any conditions for their release.
The OSCE said it had lost contact with one of its four-man monitoring teams in Donetsk on Monday evening. Rebels have previously kidnapped OSCE monitors in Ukraine.
The OSCE monitors have been deployed to Ukraine to monitor security situation following Russia's annexation of Crimea and a pro-Russia separatist insurgency that has engulfed regions in eastern Ukraine. They also observed Sunday's presidential vote.
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