His remarks followed recent talks conducted by Putin's Special Envoy for Foreign Economic and Investment Cooperation Kirill Dmitriev in Miami.
It's unlikely that all of the peace plan’s proposals will be acceptable to Russia, Ushakov said, adding that most of the proposals put forward in the negotiations with the US originated from Ukraine and Europe and are not constructive.
He affirmed that Russia will remain steadfast in the positions it discussed in Alaska last August and in other meetings with the US.