Russian President Vladimir Putin says the risk of nuclear war is on the rise, but he insists his country sees its arsenals as a purely defensive deterrent.

At Russia's Human Rights Council on Wednesday, Putin said he understands "what nuclear weapons are."

The threat of using nuclear weapons has come up several times during Russia's invasion of Ukraine.

Putin turned the conversation to a different nuclear power. He said, "The American nuclear weapons in large numbers are located on the European territory. We don't give our nuclear weapons to anybody and we are not going to, but of course we will defend our allies with all available means, if we need to."

Putin also said that the war in Ukraine may be a "long process."

The Kremlin says it launched missile attacks on eastern and southern parts of Ukraine on Wednesday.

But Russia is also focused on its home soil. Attacks this week at its air force bases have apparently raised serious concerns.

Russia's defense ministry claims Ukrainian forces used "Soviet-era drones" in those attacks.

Russian newspaper Izvestia reported that Ukraine has Tupolev-141 drones that have a maximum flight range of 1,000 kilometers.

It also said Ukrainians could have modified drones capable of ground strikes.