(NewsNation) — Russia’s Foreign Minister Sergei Lavrov said Tuesday that his country would not use nuclear weapons during its invasion of Ukraine.

Lavrov, who does not make military decisions for Russia, made his comment as Ukrainian President Volodymyr Zelenskyy continues to sound alarm bells about the possibility of Russia utilizing nuclear weapons in the war.

Russia was intensifying its attack on Ukraine’s east Tuesday as it seized a frontline city and sought a decisive victory in Mariupol, prompting Western governments to pledge more arms and sanctions.

Thousands of Russian troops backed by artillery and rocket barrages were advancing in what Ukrainian officials called the Battle of the Donbas.

Russia’s nearly eight-weeklong invasion has taken longer than many expected while still failing to capture any of the biggest cities, forcing Moscow to refocus its efforts around separatist regions in the east.

“The key we need to watch out for, over the next 96 hours, is what kind of momentum can the Russians attain as they move east and then south towards Mariupol and down to the Black Sea. The Russians are really focused on creating that land bridge from the Donbas region all the way down to Crimea,” retired Lt. Gen. Richard Newton said during a Tuesday appearance on “NewsNation Prime.”

Last week, after Ukrainian forces sank Russia’s flagship vessel of the Black Sea, Zelenskyy began voicing fears that Russia could deploy nuclear weapons.

U.S. officials at the Pentagon are keeping an eye on any possible use of nuclear weapons by Russia but said there is no reason as of right now to change deterrence policies.

“We are actively monitoring every single day, even today,” Pentagon spokesperson John Kirby said. “And even today, the secretary remains comfortable that we have an appropriate strategic deterrent posture in place and there is no need to make any changes to it.”

CIA Director William Burns last week also said the United States was taking concerns of nuclear war seriously.

“Given the potential desperation of President Putin and the Russian leadership, given the setbacks that they’ve faced so far militarily, none of us can take lightly the threat posed by a potential resort to tactical nuclear weapons or low-yield nuclear weapons,” Burns said.

U.S. President Joe Biden also said he would continue to send more weapons, including artillery, to an outgunned Ukrainian military. .