"Russia sees a need to take into account the different voices in eastern Ukraine," said Swiss President and acting OSCE chief Didier Burkhalter.
"You have seen Russia's response, that there is respect but not recognition to the referendum. There is no recognition of these results," he told journalists.
He spoke after talks with European Union foreign ministers in which Burkhalter outlined a roadmap for peace for Ukraine beginning with a national dialogue moderated by the OSCE and an independent Ukrainian figure.
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Saying "we can't lose time" in Ukraine, he said he hoped to see the dialogue launch in the next few days.
"If we want to succeed in the end it is about the integration of all actors. The integration of the Russian Federation above all is very important.
"We have seen in Moscow that there is an openness for a dialogue," said Burkhalter who met with Putin last week.
He stressed the importance of country-wide elections on May 25 and said the OSCE was planning to send 1,000 monitors to Ukraine for the vote, "one of the biggest missions" in the organisation's history.
"It is very important that we believe that the election can take place and that we act in that direction," he said.
A first step in the OSCE roadmap has been to name respected veteran German diplomat Wolfgang Ischinger as a moderator for the roundtable talks that would involve the Ukraine government, parliament and the regions.
Ischinger, who would work alongside a Ukrainian bipartisan figure, was a longtime ambassador in Britain and the US and took part in the Dayton negotiations on Bosnia as well as NATO's eastwards enlargement. He heads the Munich security conference.
