Vladimir Medinsky, head of the Russian delegation, said that Russia will consider proposals from Ukraine and will report to his President Vladimir Putin.

Ukrainian negotiators said they had proposed a status under which their country would not join alliances or host bases of foreign troops, but would have its security guaranteed in terms similar to "Article 5," the collective defense clause of NATO.

They identified Israel and NATO members Canada, Poland and Turkey as countries that could help provide such guarantees.

The proposals would include a 15-year consultation period on the status of Crimea, and could come into force only in the event of a complete ceasefire, the Ukrainian negotiators told reporters in Istanbul.