MOSCOW — President Vladimir V. Putin of Russia, in a decision that was widely expected, suspended his country’s observance of a key nuclear arms control pact on Saturday in response to a similar move by the United States a day before.

But adding to a sense that the broader architecture of nuclear disarmament has started to unravel, Mr. Putin also said that Russia would build weapons previously banned under the treaty and would no longer initiate talks with the United States on any matters related to nuclear arms control.

The Trump administration withdrew from the treaty, a keystone of the late Cold War disarmament pacts known as the Intermediate-Range Nuclear Forces Treaty, saying that Russia had been violating it for years. The decision holds the potential to initiate a new arms race, not only with Russia, but also China, which was never a signatory to the 1987 treaty.

Beijing responded to the American announcement by warning on Saturday that the breakup of the treaty would undermine global security, but also by rejecting calls for China to join an expanded version of the pact.

Mr. Putin also noted what he called progress on Russia’s development of new types of nuclear weapons not covered by the treaty, including a drone submarine called Poseidon that carries a massive thermonuclear warhead designed to detonate in shallow coastal waters, flooding the enemy’s ports and seaside cities with a radioactive tsunami.

In his remarks, the Russian minister of foreign affairs, Sergey V. Lavrov, presented a picture of the wobbly state of the whole architecture of American and Russian nuclear disarmament that had been erected over the past 50 years, beginning with the Anti-Ballistic Missile Treaty of 1972.

Mr. Lavrov suggested a number of treaties were in need of urgent review, such as the Nonproliferation Treaty that prohibits passing nuclear weapons technology to countries that do not already posses it. He argued that America had violated it by conducting nuclear deterrence training exercises with NATO nations that were not declared nuclear powers.

China’s array of nuclear weapons remains much smaller than the American and Russian forces, but Beijing has been upgrading and expanding its arsenal. Some critics of the intermediate nuclear forces treaty have argued that it unfairly ties the United States’ hands from responding effectively to China’s military buildup.

In October, President Trump cited China’s potential expansion as a reason the United States should consider quitting the treaty.

“If Russia’s doing it and if China’s doing it, and we’re adhering to the agreement, that’s unacceptable,” Mr. Trump said after a rally in Nevada.

In January, Global Times, a Chinese Communist Party-controlled tabloid newspaper with a heavily nationalist tone, reported that a People’s Liberation Army unit had carried out an exercise with an intermediate-range “ship killer” missile formally called the DF-26. China probably has 16 to 30 intermediate-range ballistic missiles, an annual Pentagon report on China’s military said last year.