Alexander Volfovich, state secretary of Belarus' Security Council, said it was logical that the weapons were withdrawn after the 1991 Soviet collapse as the United States had provided security guarantees and imposed no sanctions.

"Today, everything has been torn down. All the promises made are gone forever," the Belta news agency quoted Volfovich as telling an interviewer on state television.

Belarus, led by President Alexander Lukashenko since 1994, is Russia's staunchest ally among ex-Soviet states and allowed its territory to be used to launch the Kremlin's invasion of Ukraine in February 2022.

Russia moved ahead last week with a decision to deploy tactical nuclear weapons on Belarusian territory aimed at achieving specific gains on the battlefield.

Russia says its "special military operation" in Ukraine was aimed at countering what it says is a drive by the "collective west" to wage a proxy war and inflict a defeat on Moscow.

"The deployment of tactical nuclear weapons on the territory of Belarus is therefore one of the steps of strategic deterrence. If there remains any reason in the heads of Western politicians, of course, they will not cross this red line," Volfovich said.

He said any resort to using "even tactical nuclear weapons will lead to irreversible consequences."

Lukashenko last week said the weapons were already on the move, but it is not yet clear when they will be in place.

The United States has denounced the prospective deployment of nuclear weapons in Belarus but says its stance on the use of such weapons has not been altered.

Western sanctions were imposed on Belarus long before the invasion in connection with Lukashenko's clampdown on human rights, particularly the repression of mass protests against what his opponents said was his rigged re-election in 2020.

After independence from Soviet rule, Belarus, Ukraine and Kazakhstan agreed to their weapons being removed and returned to Russia as part of international efforts to contain proliferation.

Australian Associated Press