But Moscow has signalled it may be willing to give some ground, with a senior official telling Trump's national security adviser John Bolton that Russia is ready to address US concerns about how the 1987 Intermediate-Range Nuclear Forces Treaty is being implemented.

In Washington, the US president reiterated his concern about the treaty, telling reporters: "Russia has not adhered to the agreement. ... When they do, then we'll all be smart and we'll all stop."

He said China, too, should be included in the accord and that until all sides stopped trying to develop new intermediate nuclear arms "there will be nobody that's going to even be close to us."

Trump drew a warning of "military-technical" retaliation from Moscow after saying on Saturday that Washington would withdraw from the Cold War-era pact which rid Europe of land-based nuclear missiles.

Signed by then-President Ronald Reagan and reformist Soviet leader Mikhail Gorbachev, the treaty required the elimination of all short and intermediate-range land-based nuclear and conventional missiles held by both countries in Europe.

Its demise could raise the prospect of a new arms race, and Gorbachev, now a frail 87-year-old, has warned that unravelling it could have catastrophic consequences.

Kremlin spokesman Dmitry Peskov called Trump's withdrawal plan a matter of deep concern for Moscow. "Such measures can make the world more dangerous," he told reporters on a conference call.

Despite repeated Russian denials, US authorities believe Moscow is developing and has deployed a ground-launched system in breach of the treaty that could allow it to launch a nuclear strike on Europe at short notice.

Trump said the United States would develop equivalent weapons unless Russia and China agreed to a halt in development. China is not a party to the treaty.

Peskov said President Vladimir Putin had repeatedly warned that the demise of the treaty would compel Moscow to take specific military steps. "Scrapping the provisions of the INF treaty forces Russia to take measures for its own security because what does scrapping the INF treaty mean?" said Peskov.

"It means that the United States is not disguising, but is openly starting to develop these systems in the future, and if these systems are being developed, then actions are necessary from other countries, in this case Russia, to restore balance in this sphere."

Bolton had talks in Moscow with Nikolai Patrushev, the Secretary of Russia's Security Council, and Foreign Minister Sergei Lavrov.

In comments released after his meetings, Bolton denied Russian allegations the United States was using the threat of treaty withdrawal to blackmail Russia.

Washington had not yet taken any decision on deploying missiles in Europe targeting Moscow in the event that the INF treaty is scrapped, Russia's RIA news agency quoted him as saying.

Bolton said Russia was violating its commitments under the pact, an allegation Moscow has denied.

In any case, he added, a bilateral treaty no longer met today's realities because unlike in the Cold War, multiple states are now developing intermediate range nuclear missiles. Those states, he said, include China and North Korea.

Australian Associated Press