Russian President Vladimir Putin arrived here on Thursday for the annual India-Russia bilateral summit that he will hold with Prime Minister Narendra Modi.
External Affairs Minister Sushma Swaraj received Putin at the airport here.
"Welcome to India, President Putin," Modi tweeted.
"Looking forward to our deliberations, which will further enhance India-Russia friendship," he wrote.
Later, Modi welcomed Putin with a warm hug at 7, Lok Kalyan Marg before the two sat down for a private meeting.
Around 20 agreements are expected to be signed between the two sides following the 19th India-Russia Bilateral Summit to be held here on Friday.
This includes India's purchase of four S-400 air defence missile systems from Russia at a cost of more than Rs 40,000 crore.
The deal has been an issue of much speculation after US President Donald Trump's administration's law — Countering America's Adversaries Through Sanctions Act (CAATSA) — came into effect in January.
CAATSA targets countries doing business with Russian, Iranian and North Korean defence companies.
Russia is one of only two countries with which India holds annual bilateral summits, the other being Japan.
The India-Russia bilateral relationship was elevated to Special and Privileged Strategic Partnership in 2010.
This is the third meeting between Modi and Putin this year after the informal meeting in the Russian resort city of Sochi in May and a bilateral on the sidelines of the BRICS Summit in South Africa.