Prime Minister Vladimir Putin earlier said Russia would provide $20 million to Cuba, which would be used to buy Russian-made goods.

"The visit will see a series of documents, including an inter-government agreement on a state loan and food aid to Cuba," a Kremlin official said, adding that 25,000 metric tons of grain would be delivered to the country "to ease an acute food problem."

Castro, the first Cuban leader to visit Russia since 1985, will have formal talks with President Dmitry Medvedev on Friday. Castro arrived in Moscow on Wednesday and is due to depart on February 4.

Thursday saw the two leaders enjoy a nostalgia-tinted meeting at the presidential Soviet-era country residence of Zavidovo.

Relations between Cold War allies Russia and Cuba declined after the collapse of the Soviet Union. However, in recent years, Russia has moved to revive ties with Cuba, as well as other Latin American states. Medvedev visited Havana in November, holding talks with Raul Castro and his elder brother and the country's former leader Fidel.

Medvedev and Castro will discuss further economic, political and humanitarian cooperation at talks on Friday, a Kremlin official said.