On Monday, Indian Prime Minister Narendra Modi visited Russian President Vladimir Putin in New Delhi, where they discussed trade as well as the deteriorating situation in Afghanistan.

The Taliban’s takeover of Afghanistan earlier this year has resulted in a humanitarian catastrophe, which both New Delhi and Moscow have already stated threatens destabilizing the region.

“The war against terrorism is also a struggle against drug trafficking and organized crime,” Putin said during his opening remarks, which were carried by Indian media. “In that context, we are concerned about the events in Afghanistan.”

The visit by Putin and several top Russian officials comes amid increasingly strained relations between Russia and the United States, also a key Indian ally.

Earlier on Monday, Russian Foreign Minister Sergei Lavrov said a deal to supply India with S-400 air defense missile systems was being implemented despite what he said were U.S. efforts to undermine the accord.

India and Russia are expected to cement several trade and defense pacts at the summit.

“The relation between India and Russia is truly a unique and reliable model,” Modi said.