Two OSCE monitors watch during a pro-Ukrainian rally in the eastern Ukrainian city of Lugansk on April 19, 2014.
The OSCE today said that a team of negotiators is heading to Slavyansk in eastern Ukraine to try and secure the release of eight military monitors held by pro-Russian militants.
"They are expected to be in the region today (Sunday)," Organisation for Security and Co-operation in Europe spokeswoman Tatyana Baeva told AFP.
"We hope to be able to provide more information once they arrive and when they start talking -- if they start talking."
She was unable to say how many negotiators were heading to the flashpoint eastern town, where the four Germans, one Pole, one Czech, one Swede and one Dane were seized on Friday together with five Ukrainians.
The negotiators being sent form part of a separate, 100-strong special monitoring mission by the Vienna-based pan-European security body who are already on the ground in Ukraine.
Russia, a member of the OSCE, pledged yesterday to "take all possible" steps to secure their release, with Ukraine's SBU security service saying they were being held in "inhuman conditions", with one "urgently" needing medical help.
The insurgents in Slavyansk, which they seized two weeks ago, says that the OSCE military observers are "NATO spies" and that they can be "exchanged for our own prisoners".