Russians bear a "holy duty" to be patriotic as the country commemorates the 74th anniversary of Nazi Germany's invasion of the Soviet Union, President Vladimir Putin said.

"It's our holy duty to be faithful to the great values of patriotism, to keep the memory of our fathers' and grandfathers' achievements, and to honor our veterans," Putin said on Monday during a televised ceremony honoring cities for their sacrifices during the war.

The Chechen capital Grozny, Staraya Russa in the Novgorod region, the Leningrad region town of Gatchina, Karelia's Petrozavodsk, and the Crimean port Feodosia were also named "Cities of Military Glory" in the Kremlin ceremony.

Putin, who also laid a wreath at Russia's Tomb of the Unknown Soldier, has appealed to patriotism to rally support as the economy heads for its first recession since 2009. Sergei Ivanov, the Kremlin chief of staff, told reporters on Monday that he wasn't surprised the European Union decided to extend sanctions on the war anniversary.