US President Donald Trump's recent nuclear wake-up call has aroused alert and vigilance on the Russian side and could risk setting off a new Cold War-style nuclear arms race between Washington and Moscow, observers say.

Trump, in an interview with the Reuters news agency in the Oval Office on Thursday, expressed his dissatisfaction with the New START Treaty and declared the aim of ensuring the US nuclear arsenal "at the top of the pack".

Analysts believe that if the United States gives up the nuclear balance of power adopted by past US administrations and resorts to unilateral advantages, US nuclear arsenal expansion would make US-Russian relations more complicated and take the bilateral relationship toward a dead end.

RUSSIA FEARS "RETURN TO COLD WAR"

In the Reuters interview, Trump called the New START Treaty, or the new Strategic Arms Reduction Treaty, "one-sided" and "a bad deal" for Washington.

The pact was signed by the United States and Russia in 2010. Following ratification by the US Senate and the Federal Assembly of Russia, the treaty went into force in 2011. Under the treaty, the two nations agreed to cut the number of deployed nuclear warheads to 1,550 and the number of deployed missiles and bombers to 700. The treaty is expected to last until 2021 and it may be extended for a period of no more than five years.

Trump said the United States was going to be "at the top of the pack" in terms of nuclear capacities and would never "fall behind on nuclear power".

He also complained that the Russian deployment of a ground-based cruise missile is in violation of the Intermediate-Range Nuclear Forces Treaty (INF Treaty), an agreement signed by the United States and the Soviet Union in 1987.

Asked if he would raise the issue with Russian President Vladimir Putin, Trump said he would do so "if and when we meet." But he had no meetings scheduled as of yet with Putin.

Trump's words have made a big splash in Russia. Leonid Slutsky, chairman of the Russian lower house of parliament's international affairs committee, said if Washington seriously aims for the dominance in nuclear sphere, a return to cold war and arms race will be inevitable.

Konstantin Kosachev, chairman of the international affairs committee in the upper house of the Russian parliament, said Trump's words are arguably the "most alarming statement" on the subject of relations with Russia.