Russia's President Vladimir Putin compared the Israeli siege of Gaza to the Nazi blockade of Leningrad during World War II, as he called it "unacceptable" on Friday.

Israel is now about to do something that is "comparable to the siege of Leningrad during the Great Patriotic War," Putin told journalists in Kyrgyzstan. "In my opinion, this is unacceptable," he said.

Fears for Gaza's Palestinian inhabitants have grown since the Israeli army called for 1.1 million people – nearly half the territory's total population – to evacuate ahead of a possible ground invasion.

"We understand what that entails. In my opinion, this is unacceptable. More than two million people live there," he added.

Moscow, which manages to retain close relations with both the Israeli and Palestinian authorities, said on Monday that creating a Palestinian state was the "most reliable" solution for peace in Israel.

Putin renewed his call for negotiations on Friday and offered Moscow as a potential mediator.

When asked whether Moscow could help find a way to end the crisis, Putin said: "Russia can, by virtue of the fact that we have had good relations with Israel over the last 15 years."

Putin previously said the Israel-Gaza conflict showed the "failure" of Washington's Middle East policy and called the creation of "an independent sovereign Palestinian state" a "necessity."