Prime Minister Narendra Modi and Russian President Vladimir Putin on Thursday signed a deal for the supply of S-400 Triumf missile system from Moscow to New Delhi.

The deal was signed despite a warning by the United States that it would impose sanctions on India if the agreement went through. Under new US laws, countries that sign deals with Russian defence or intelligence sectors can face secondary sanctions.

The two countries also signed memoranda of understanding related to railways, space and nuclear energy. “India gives priority to its relations with Russia,” ANI quoted Modi as saying at a joint press conference. “Russia has always been a part of India’s growth story.”

The two countries have mutual benefits in supporting Afghanistan, the struggle against terrorism, Indo-Pacific events and climate change, the prime minister said. He added that the two would continue cooperation at international groups such as the Shanghai Cooperation Organisation, BRICS, G-20 and the Association of South East Asian Nations.

Putin said he has invited Modi to be the main guest at the next Eastern Economic Forum, which was set up to encourage foreign investment in the far eastern regions of Russia.

The Russian president said he had also discussed the situation in Syria with the Indian prime minister. “We have also discussed the situation that came as a result of action of US to withdraw from Iran deal,” Putin added. Russia is involved in a civil war in Syria and is providing military support to President Bashar al-Assad along with Iran.

Putin arrived in New Delhi on a two-day visit to India. A high-level delegation comprising Deputy Prime Minister Yuri Borisov, Foreign Minister Sergey Lavrov and Trade and Industry Minister Denis Manturov is accompanying him.

Modi and Putin previously met in Johannesburg during the BRICS summit in July and in May in Russia’s Sochi after Putin’s re-election.