The agreement likely will include provisions that part of the debt, incurred during the Soviet Union era, to be written off and part of it to be restructured, RIA Novosti reported.
Russian and Cuban officials initialed the debt settlement agreement, which allows discussions to continue and procedures to be developed before it goes into effect, Manturov said.
"There was an accumulated debt of Soviet Union-granted loans and now an agreement has been drafted, which does not yet enter into force but is initialed until all coordination procedures are conducted," Manturov said.
Russia is the Soviet Union's legal successor for loan repayment, RIA Novosti said.
Russian Deputy Foreign Minister Sergei Ryabkov and Ricardo Cabrisas, vice president of the Cuban Council of Ministers, signed the document in the presence of Cuban leader Raul Castro and Russian Prime Minister Dmitry Medvedev, who arrived in Cuba Thursday after he visited Brazil.
Manturov did not indicate how much of the debt would be forgiven.