The United States called on India on Wednesday to distance itself from Russia, its main arms supplier, after the invasion of Ukraine, which New Delhi has yet to condemn. New U.S. sanctions on Russian banks will make it harder for countries to buy major defence equipment from Moscow, a U.S. diplomat said, though no decision had been reached on Washington granting a waiver to New Delhi to take delivery of Russian surface-to-air missiles under an earlier contract.

India signed a $5.5 billion deal with Russia in 2018 to buy five of its S-400 missile systems, initial supplies of which started late last year despite a U.S. law aimed at deterring countries from buying Russian military hardware.

The United States this week placed more restrictions on Moscow including the bank sanctions after Russia invaded Ukraine last week.

“It is going to be very hard for any country in the globe to buy major weapon systems from Russia because of the sweeping sanctions now placed on Russian banks,” Donald Lu, assistant U.S. secretary of state for South Asian affairs, told a U.S. senate subcommittee.

Lu also said U.S. officials have held talks with India to “underscore the importance of a collective response condemning Russia’s invasion”. India is the only major U.S. ally that has declined to publicly criticise Moscow, though it has called for an end to violence.

Asked by senators if the Ukraine crisis had changed the administration’s position on a waiver for India, he said:

“I am not able to prejudge the decisions of the president or the secretary on the waiver issue or on the sanction issue, or whether Russia’s invasion of Ukraine will bear on that decision,” Lu said.

“What I can say is that India is a really important security partner of ours now, and that we value that partnership. Moving forward, I hope that part of what happens with the extreme criticism that Russia has faced is that India will find it is now time to further distance itself from Russia.”

India’s foreign ministry did not immediately respond to a request for comment.

Russia is India’s main arms supplier, though since 2011 New Delhi has reduced its imports from Moscow by 53% and raised purchases from the United States.