US allies including Britain, France and Germany in Europe and Japan and Australia in the Indo-Pacific region have been lobbying US President Joe Biden not to alter existing US nuclear policy to include a "no first use" declaration, The Financial Times reported Friday.

Allies share concerns that the Congressionally mandated nuclear policy posture review could undermine long-established deterrence efforts aimed at Russia and China.

While some allies believe Biden will refrain from alterations to the existing policy, which has not changed much since the end of the Cold War, many are concerned Biden could consider a policy referred to as "sole purpose."

Any changes that could inhibit the perception that the US would confine itself to the use of nuclear weapons in a prescribed set of circumstances triggers fears among allies that the "nuclear umbrella" of US allies would weaken and "be a huge gift to Russia and China," in the words of one European official quoted by The Financial Times.

Hopes for clarification from Biden at the G20 summit

US allies do not want to see the US restrict itself to permitting the use of nuclear weapons only to deter an attack on the US or to retaliate.

Allies reportedly want to hear from Biden over this weekend's G20 leaders' summit in Rome, Italy that changes will not be made restricting America's use of nuclear weapons.

On Friday, Biden met with French President Emmanuel Macron and the joint statement that followed the encounter included a commitment to "a credible and united nuclear alliance" as well as a promise of "close consultations" on nuclear matters.

When US Secretary of Defense Lloyd Austin visited NATO headquarters in Brussels earlier this month, allies reportedly engaged in intense lobbying to prevent any substantive changes to US nuclear policy.

Pentagon spokesman John Kirby said consultations with allies were "essential and ongoing" as the administration wrapped up the nuclear posture review, expected before the end of the year.

Kirby added, "Our US extended deterrence commitments remain strong and credible."