Modi will be travelling to St Petersburg on June 1 to attend the St Petersburg International Economic Forum (SPIEF).
On the sidelines, he is expected to have talks with Russian President Vladimir Putin to review the state of bilateral relations and ways to push the ties further.
However, it is not clear whether the General Framework Agreement (GFA) for setting up of units 5 and 6 of the Kudankulam Nuclear Power Plant (KNPP) will be signed during the Prime Minister's visit.
"After its evaluation by the inter-ministerial group, the proposal has now been sent to the PMO and is awaiting its green signal," the source said.
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The issue related to the GFA had figured in the talks between the two countries last week when Russian Deputy Prime Minister Dmitry Rogozin was here to prepare the ground for the bilateral meet between Modi and Putin.
Rogozin had co-chaired an inter-governmental commission meeting with External Affairs Minister Sushma Swaraj where the two sides agreed to take forward collaborative projects in a range of sectors, including nuclear energy, and joint projects in third countries.
Government sources said the GFA between India and Russia was to be signed by December last year but it has been pending because of disagreement between the two sides over credit protocol.
The delay also comes against the backdrop of concerns in India over Russia's growing proximity with Pakistan. India also wants Russia to make more efforts to get it into the elite Nuclear Suppliers Group (NSG).
Unit 1 and 2 of the KKNPP are already operational.
In August 2016, Modi and Putin jointly dedicated Unit 2 of the plant to "India-Russia Friendship and Cooperation" and witnessed the laying of foundation concrete for KKNPP units 3 and 4 through video-link.