New Delhi: Prime Minister Manmohan Singh on Thursday left on a three-day visit to Moscow, where he is to hold a summit meet with Russian President Dmitry Medvedev when the two nations will sign key agreements in the defence, health and science, and technology fields, besides discussing key deals in nuclear energy and hydrocarbons sectors.

The Prime Minister, who will be in Moscow till Saturday, will also hold a one-on-one meeting with Russian premier Vladimir Putin, who is at the centre of a political upheaval over allegations of rigging in elections to Duma December 4 following which protests have erupted on the streets of Moscow and otehr cities.

Among the key issues that Manmohan Singh will discuss with Medvedev is a deal on setting up of units III and IV of the Kudankulam Nuclear Power Plant in Tamil Nadu, where villagers are protesting for the last 10 months against the first two units following the Japanese Fukushima nuclear plant disaster early 2011.

Defence deals such as the USD2.34-billion Admiral Gorshkov aircraft carrier and its scheduled delivery in December 2012, the fifth generation fighter aircraft, and multirole transport aircraft for the military are expected to figure in the discussions.