Russian President Vladimir Putin and Indian Premier Narendra Modi looked to bolster declining trade Thursday, as the defiant Russian strongman sought to burnish a fragile recovery at the Kremlin's economic showcase despite tensions with the West.

Among the deals Modi and Putin oversaw on the third leg of the Indian leader's four-nation tour of Europe was the inking of an agreement for Moscow to build two more reactors at a nuclear plant in southern India.

Modi is the guest of honour at this year's three-day Saint Petersburg Economic Forum ─ Russia's answer to Davos ─ that Putin wants to use to push the idea that Russia has turned the page on a brutal recession caused by low oil prices and sanctions over Ukraine.

Speaking to journalists as the showcase kicked off, the combative Kremlin strongman insisted that measures against Moscow, including economic sanctions, had ended up having “zero effect”.

Putin said he hoped “Russophobia” in the West would “not last for too long, not forever, if only because the understanding has to come that it is counterproductive and harms everyone.” He again struck out at allegations the Russian state was behind hacking attacks targeting elections in the West after accusations he meddled in the last year's US vote but did hold out the possibility that “patriotically minded” hackers might have been involved.

“If they are patriotically minded, they start making their own contribution which they deem right in the fight against those who demean Russia,” he said.

“Theoretically this is possible.But we are not involved at the state level.”

India ties

For the Kremlin, India represents the sort of major emerging market it wants to do more business with as it looks to insulate itself against geopolitical shocks with the unpredictable Donald Trump in the White House.

“Russian-Indian economic cooperation is once again heading in the direction of growth and it is in our shared interests to strengthen this positive tendency,” Putin said at a joint press conference with Modi.

Russia and India enjoyed a decades-long alliance forged during the Cold War, when the Soviet Union was New Delhi's largest trading partner, diplomatic ally and main arms supplier, providing everything from tanks to aircraft.

But the relationship became unmoored following the collapse of the USSR, as India underwent an economic transformation and increasingly sought to build trade ties with Western nations.

US businesses back?

While India is occupying pole position at the forum, other visiting international leaders include UN Secretary General Antonio Guterres and Austrian Chancellor Christian Kern.

Bosses from Chevron, Exxon and Boeing are among 144 US firms at the event, the best attendance in years after Washington previously warned business leaders against attending due to political tensions.

While Russia is talking up its recovery, the situation remains precarious and attention will also focus on talk of much-needed reforms to modernise its creaking economy.

But analysts warned that with Putin likely to bid for another term as president in elections next year there are unlikely to be any radical changes.

“Structural changes are necessary but to put them into action is not easy,” Russian Finance Minister Anton Siluanov said.