Russian President Vladimir Putin will not abandon Russians living in south-east Ukraine to Ukrainian nationalists, the state-run RIA news agency quoted him as saying in a documentary due to be broadcast later on Sunday.
Moscow says Ukrainian nationalists pose a threat to ethnic Russians and Russian-speaking Ukrainians in the region. More than 9,000 people have been killed in fighting in eastern Ukraine between Russian-backed separatists and Ukrainian troops since April 2014.
"We proceed from only one thing, which is we cannot just abandon the people who live in the southeast of the country to nationalists to eat them up," Putin said.
"There is nothing excessive in that position."
He did not elaborate.
Putin has denied allegations by independent observers and media that Russian regular troops are taking part in the conflict. However, on Friday he admitted that Russia did have personnel in eastern Ukraine who were carrying out certain military tasks.
According to RIA, Putin also said Russia would continue to improve its nuclear arsenal, but added that it would not wield the "nuclear big stick".