Russian President Vladimir Putin has said Ukraine's assault on its eastern cities is reminiscent of the Nazi siege of Leningrad.
"Small villages and large cities surrounded by the Ukrainian army which is directly hitting residential areas... It sadly reminds me the events of the Second World War, when German fascist... occupants surrounded our cities," he told a youth camp outside Moscow.
Mr Putin urged Kiev to begin "substantive" negotiations with the separatists to achieve peace, adding that Russians and Ukrainians are "practically one people".
"It is necessary to force the Ukrainian authorities to substantively begin these talks - not on technical issues… the talks must be substantive," Mr Putin said.
He also said Russia needed to strengthen its position in the Arctic, economically and militarily.