Russia and the US have officially extended the New Strategic Arms Reduction Treaty (New START) by five years as the agreement on the extension of the key nuclear pact has entered into force, authorities from the two countries have confirmed.

In a statement issued on Wednesday, the Russian Foreign Ministry said that it exchanged diplomatic notes on the completion of all domestic procedures required for the treaty's extension with the US Embassy, Xinhua news agency reported.

"The New START treaty will operate in the form it was signed, without any changes or additions, until February 5, 2026," it added.

According to the Ministry, the telephone conversation between the Presidents of Russia and the US on January 26 was key for this development to proceed.

"We hope that the understanding reached with Washington regarding the fate of the landmark treaty for international security will help overcome the tendency that has prevailed in recent years as a result of the destructive US policy on breaking arms control and non-proliferation mechanisms," it emphasized.

The Ministry was added that Russia is ready to continue constructive dialogue with the US to achieve new results that would strengthen the strategic stability in the world.

Also confirming the development, US Secretary of State Antony Blinked said: "Extending the New START Treaty ensures we have verifiable limits on Russian ICBMs, SLBMs, and heavy bombers until February 5, 2026."

He added that the extension "makes the US, allies and partners, and the world safer", adding that "especially during times of tension, verifiable limits on Russia's intercontinental-range nuclear weapons are vitally important".

Blinken noted that Washington would use the five-year extension period to seek arms control with Moscow that addresses all of the Russian nuclear weapons.

The New START, which limits the numbers of deployed strategic nuclear warheads to 1,550 and delivery systems to 700 for each, is the last remaining nuclear arms control pact in force between the two nuclear superpowers.

The treaty can be extended by a maximum of five years with the consent of the two countries.

The former administration of President Donald Trump tried to conclude a shorter extension of the treaty last year after rounds of negotiation with Russia, but the two sides failed to finalise a formal agreement.

Immediately after taking office, President Joe Biden proposed a full five-year extension of the treaty that expires on February 5, a move welcomed by the Kremlin.

Russian President Vladimir Putin on January 29 signed a bill into law ratifying a five-year extension of the New START with the US.

The extension of the New START might be a bright spot for the US-Russia relations, but the overall tensions between Washington and Moscow are unlikely to decrease given their differences on issues of human rights, Ukraine, cybersecurity as well as their mutual accusation of interference in the domestic politics.