India, the world's top buyer of Russian arms and seaborne oil, has rolled out the red carpet for Putin during his two-day state visit, his first to New Delhi since Russia's invasion of Ukraine in 2022.
But New Delhi is also in talks with the US on a trade deal to cut punitive tariffs imposed by President Donald Trump on its goods over India's purchases of Russian oil.
India's energy imports are expected to fall to a three-year-low this month following US tariffs and sanctions. Russia has said it wants to import more Indian goods in an effort to grow trade to $US100 billion by 2030.
Putin said Moscow was ready to continue ensuring "uninterrupted fuel supplies" to India, following up on comments questioning US pressure on India to curb oil purchases from Russia.
India appeared cautious about the offer.
Asked about the future of energy trade between the two countries, India's foreign secretary said Indian energy companies take decisions based on "evolving market dynamics" and "commercial issues that they confront while sourcing their supplies", indicating the pressures of sanctions and prices.
Energy co-operation between the two countries continues within this framework, Vikram Misri told a media briefing. Underlining this caution, Indian state refiners Indian Oil Corp and Bharat Petroleum Corp have placed January orders for the loading of Russian oil from non-sanctioned suppliers due to widening discounts, Reuters reported.
Describing India's enduring partnership with Russia as "a guiding star", Modi said: "Based on mutual respect and deep trust, these relations have always stood the test of time."
"...we have agreed on an economic co-operation program for the period up to 2030. This will make our trade and investment more diversified, balanced, and sustainable," he told reporters, with Putin by his side.
Modi, who warmly embraced Putin on the airport tarmac when he arrived on Thursday, also reiterated India's support for a peaceful resolution to the war in Ukraine.
A joint statement issued following the summit said: "The leaders emphasised that in the current complex, tense, and uncertain geopolitical situation, Russian-Indian ties remain resilient to external pressure."
Putin received a ceremonial welcome on Friday on the forecourt of Rashtrapati Bhavan, the colonial-era presidential palace, with a 21-gun salute as his convoy drove in.
Among the deals signed, the two countries agreed to help Indians move to Russia for work, to set up a joint venture fertiliser plant in Russia, and boost co-operation in agriculture, healthcare and shipping.
They also agreed to reshape their defence ties to take account of New Delhi's push for self-reliance through joint research and development, as well as the production of advanced defence platforms.
In an interview with broadcaster India Today, Putin challenged US pressure on India not to buy Russian fuel.
"If the US has the right to buy our (nuclear) fuel, why shouldn't India have the same privilege?" he said, adding that he was ready to discuss the matter with Trump.
India has said Trump's tariffs are unjustified and unreasonable, noting continued US trade with Moscow.
