Russia will develop rockets that will be banned in the Cold War if the US leaves the pact, warned President Vladimir Putin.
His remarks follow Tuesday's NATO accusation that Russia has already broken the Nuclear Forces (INF) Treaty.
The agreement, signed in 1
987 by the United States and the USSR, prohibits both countries from using short range and medium range missiles.
But Putin says the allegation is an excuse for leaving the US for the US.
In television commentaries, the Russian leader said many other countries had developed weapons that were banned under the INF Treaty.
"Now it seems that our American partners believed that the situation has changed so much that [they] must also have such a weapon," he said.
"What's our answer? It's easy – in that case we'll do that too."
US President Donald Trump has previously said that the country would leave the treaty because of Russian action.
According to analysts, Russia sees weapons as a cheaper alternative to conventional forces.
What did NATO say?
On Tuesday, the Western military alliance formally accused Russia of breaking the treaty.
"The Allies have come to an end that Russia has developed and deployed a missile system, the 9M729, which violates the INF Treaty and poses significant risks to Euro-Atlantic security," the statement said.
The statement states that member states "strongly support the American claim that Russia is violating the pact and urged Moscow to return urgently to full and verifiable compliance".