VIENNA A Russian ambassador said on Monday it had been "extremely irresponsible" to send military monitors from the Organisation for Security and Cooperation in Europe to eastern Ukraine, where they were detained by pro-Russian rebels last week.
Andrey Kelin, Moscow's ambassador to the Vienna-based OSCE, said however it would be a good step towards easing the conflict to release the seven European monitors, who are being held in the city of Slaviansk.
Asked what Russia was doing to help achieve that, Kelin told reporters: "We are doing some steps, not only by statements, but also in practice." He gave no further details.
A senior U.S. diplomat called on Russia to secure the "unconditional and immediate release" of the German-led team.
"We remain disappointed that senior officials in Moscow have not condemned the abduction - nor have they demanded the team's immediate release," Gary Robbins, deputy head of the U.S. mission to the OSCE, told an extraordinary meeting of the 57-nation European security body.
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.
Kelin said people in eastern Ukraine were under the "threat of military operation", making clear he meant by the Kiev government which he suggested had some 11,000 troops as well as hundreds of tanks at its disposal.
"People (are) expecting an aggression ... every moment, so it is extremely tense. That is why it was extremely irresponsible to direct (monitors) to this region in this tense situation," Kelin said after the closed-door OSCE meeting.
It was "quite an adventure or provocation ... to bring these people to a hot spot," he added.
Germany urged Moscow earlier on Monday to use its influence on the separatists to secure the release of the observers.
Kelin said an OSCE mission was "doing a lot to liberate them and to get them free and we in Moscow ... feel that liberation of these military monitors will be a good step for de-escalation of the conflict."
Washington says armed rebels - who have captured towns and government buildings across eastern Ukraine and are also holding a number of Ukrainians - are operating under the direction of Kremlin agents. Russia denies it is involved and says the uprising is a spontaneous response to oppression of Russian speakers by Kiev.
(Editing by Robin Pomeroy)