The Organization for Security and Cooperation in Europe has re-established contact with two groups of monitors who went missing in eastern Ukraine at the end of May, an OSCE Special Monitoring Mission spokesman told Interfax-Ukraine on Thursday.

None of the groups has been freed so far, the spokesman said.

The first group of OSCE monitors, among them citizens of Switzerland, Estonia, Turkey and Denmark, went missing in the Donetsk region on May 26. Contact with the second team of four was lost during their trip to the Luhansk region on May 29.

OSCE Special Monitoring Mission spokesman Michael Bociurkiw said recently that none of the militia groups in southeastern Ukraine had claimed responsibility for abducting the OSCE observers.

The Ukrainian Foreign Ministry said that the OSCE monitors had been captured by "armed opponents" of the Kyiv authorities.