Russia will likely need two to four years to restore its military to pre-Ukraine war strength, Estonia’s defense minister said on Tuesday, urging continued pressure to keep Moscow in check.

During a visit to Washington, Defense Secretary Hanno Pevkur predicted a long war and called on the West to stand by the Ukrainians until they achieve victory for “the free world”.

As Russia turns to suspected Iranian kamikaze drones to attack Ukraine, Pevkur said he’s heard reports that Moscow’s arsenal is so depleted that it’s using its S-300 air defense system as ordinary missiles and that Russian shells are detonating in the air because this is the case are too old.

“There is more or less consensus that it will take two to four years for Russia to restore some capabilities or even the same capabilities it had before the war,” he said at a roundtable with correspondents from the State Department and the Pentagon .

He said Western sanctions had particularly hurt aircraft production and helicopter maintenance by depriving Russia of key components.

“If we can find new ways to influence Russia with the sanctions, we definitely have to do that,” Pevkur said.

Pevkur, who met with US Secretary of Defense Lloyd Austin, warned that Russia still has the ability to conduct attacks, including on NATO members like Estonia.

However, he downplayed the possibility of a nuclear strike, an option Russian President Vladimir Putin threatened when he announced the annexation of Ukrainian territory.

Russia has already “scared Ukraine” with its conventional attacks, Pevkur said.

“I don’t see any positive, additional added value for Russia” from a nuclear strike, he said.

“The only thing that can happen is that by doing so they would lose their silent supporters like China or some others.”