The United States is planning to deploy nuclear weapons to the UK for the first time in 15 years, The Telegraph reported, citing Pentagon documents. However, US defense official had neither confirmed nor denied the reports.

The report comes amid heightened tensions between NATO and Russia over the Ukraine conflict, and calls from some Western politicians to prepare for a potential armed clash with Moscow.

The British newspaper cited procurement contracts for a new facility at the Royal Air Force station at Lakenheath in Suffolk, which point to Washington’s intention to bring nuclear weapons to the base. RAF Lakenheath is expected to house B61-12 bombs that are three times more powerful than those dropped on Hiroshima in 1945, the Telegraph said. The US sent F-35 nuclear-capable fighters to the base last year.

Russian Foreign Ministry spokeswoman Maria Zakharova said last year that Moscow would be compelled to enact “compensatory countermeasures” if American nuclear warheads were to return to Britain. Russia has accused the West of stoking tensions in Europe and maintains that the eastward expansion of NATO is one of the root causes of the Ukraine conflict.

High-ranking European officials, including German Defense Minister Boris Pistorius, have spoken of the need to brace for a potential war with Russia. Last week the chair of the NATO Military Committee, Admiral Rob Bauer, urged the bloc to be “readier across the whole spectrum” for direct confrontation.

The head of Russia’s Foreign Intelligence Service, Sergey Naryshkin, dismissed the claims that Moscow was planning an offensive against NATO as “information warfare” aimed at justifying “hybrid aggression.”