Singh, who arrived in Moscow on Sunday, was given a warm send off at the VVIP Vnukovo-2 airport in Moscow.
The Prime Minister had on Monday met Russian President Dmitry Medvedev and Prime Minister Vladimir Putin and discussed a wide range of issues, including terrorism.
On Monday, the two sides signed a path-breaking civil nuclear agreement that will guarantee uninterrupted uranium fuel supplies for Indian atomic reactors and transfer of technology.
The deal is seen as going much forward for the benefit of India than the historic 123 atomic agreement with the United States which does not guarantee fuel supplies without any break.
Singh had described the Inter-Governmental framework agreement for civil nuclear cooperation as a 'major step' forward and said India was 'very satisfied' at the development of bilateral atomic cooperation.
Image Russia's President Dmitry Medvedev shows the way to India's Prime Minister Manmohan Singh as they meet in Moscow's Kremlin on Monday
Photograph: Alexander Nemenov / Reuters