Russian Security Council Deputy Chairman Dmitry Medvedev said the United States’ alleged “abduction” of former Venezuelan President Nicolas Maduro violated international law and could be considered an act of war by Caracas.

Speaking in an interview with Reuters, TASS and Russian war blog WarGonzo from his residence outside Moscow, Medvedev said: “What happened to President Nicolas Maduro is certainly a violation of all rules of international law.”

He added that the incident undermined the entire system of international relations, saying that if a foreign power were to “abduct” U.S. President Donald Trump, Washington would undoubtedly regard it as an act of war.

In separate remarks, Medvedev warned that allowing the New START nuclear arms control treaty to expire without a replacement should alarm the world, as it would mark the first time since the early 1970s that there would be no limits on the world’s major nuclear powers.

“I do not want to say that this immediately means catastrophe or the start of a nuclear war, but it should still concern everyone,” he said.

Medvedev said arms control treaties had played a crucial role not only in limiting the number of nuclear warheads, but also in verifying intentions and ensuring a degree of trust among major nuclear powers.