Cuban President Raul Castro was served salted boar's fat and vodka on Thursday in a nostalgia-tinged lunch at a former Politburo hunting lodge he and his brother Fidel visited two decades ago.

"I recalled with nostalgia the moment when we roasted salted salo (salted pork fat) in the forest," Castro told Russian President Dmitry Medvedev.

"I don't know if I will eat salo with brown bread this time but I am here," Castro told Medvedev as the two sat in front of a fireplace in Zavidovo, a presidential residence in the Tver region west of Moscow previously used by Soviet leaders.

During the Cold War, Cuba was a key ally for Moscow in its standoff with the United States and Fidel Castro and his younger brother Raul, then an aide, were frequent guests at the Kremlin and the Zavidovo lodge.

Relations cooled after the collapse of the Soviet Union, in part because the economic meltdown that followed left Russia with no cash to continue subsidising its Caribbean ally.

But in the past few years a resurgent Russia had renewed its interest in Latin America, including in Cuba. In November, Medvedev visited Havana for talks with Raul Castro and a brief meeting with ailing former leader Fidel.

"I am very glad to see you not only in Russia but in this forest location where you have been before," Medvedev told the Cuban leader on Thursday.

"It was a long time ago and we are very glad that your visit is taking place after practically 25 years."

Raul Castro is the first Cuban leader to visit Moscow since his older brother came for a Communist Party Congress in 1986. Raul Castro last came to Moscow in 1984 for the funeral of a Soviet official.

Medvedev on Thursday took Castro on a walk through the forest at Zavidovo and the two leaders shared a meal.

Formal talks will take place on Friday in the Kremlin. Russian Foreign Minister Sergei Lavrov has said Russia and Cuba plan to sign a series of agreements, including on energy cooperation.