MOSCOW, August 27 (RIA Novosti) - The legendary Soviet-era children's writer and poet Sergei Mikhalkov, who penned the lyrics to the Soviet and modern Russian national anthems, died on Thursday at the age of 96.

President Dmitry Medvedev has expressed condolences to the poet's widow, sons and other family members. Mikhalkov died in hospital in Moscow.

"He died of old age - he simply fell asleep," his grandson, Russian film producer Yegor Konchalovsky, said.

Mikhalkov was hospitalized with a heart attack in February, but in March was back home celebrating his 96th birthday with his family.

Mikhalkov became popular in the 1930s, especially as the author of children's poetry about giant Uncle Styopa.

In 1943, at the height of World War II, Joseph Stalin commissioned a new anthem, with the lyrics to be written by Mikhalkov. The poet along with war correspondent Ureklyan worked on the words, to music by Alexander Alexandrov, and the anthem was first performed in January 1944.

Mikhalkov altered the initial lyrics, which mentioned Stalin's name, in the 1970s. After the breakup of the Soviet Union, the anthem was briefly abolished by President Boris Yeltsin but restored under President Vladimir Putin. A new version of Russia's national anthem was officially adopted in 2001, after Mikhalkov was picked once again to write new lyrics to Alexandrov's music.

Mikhalkov was also the author of satirical plays and Soviet movie scripts.

In present-day Russia, Mikhalkov is better known as the father of two leading film makers - Nikita Mikhalkov and Oscar-winning Andrei Konchalovsky.

On his 90th birthday in 2003, Putin visited Mikhalkov at his home, decorating him with an Order for Service to the Fatherland and recognizing his contributions to Russian culture. During the Soviet era, Mikhalkov received a series of major awards, and the highly prestigious Stalin prizes.

St. Petersburg Governor Valentina Matviyenko said in a message of condolences: "Sergei Vladimirovich Mikhalkov was known and loved by several generations of Russians - his oeuvre went down in the golden stock of our literature. A whole era in the life of our country was connected to him."

Korolyov, a writer and literary critic, said: "This is a great loss to our culture, and to our literature - Mikhalkov was a symbol of a whole era."

Grandson Yegor Konchalovsky said the funeral would most likely take place on Saturday.

Apart from his two sons, Mikhalkov is survived by his wife, 10 grandchildren and several great grandchildren.