Russia is still building up its troops on the Ukrainian border, NATO chief Jens Stoltenberg said ahead of a meeting of the alliance's defence ministers on the crisis.
Russia's defence ministry announced on Tuesday that some military units had completed their training activities and would move away from the border.
But the US and its allies have expressed scepticism over this claim.
The Kremlin has repeatedly denied that they are planning an invasion despite amassing troops near Ukraine's border.
"We have not seen any withdrawal of Russian forces and, of course, that contradicts the message of real diplomatic effort [from Russia]," Stoltenberg said.
"What we have seen is they have increased the number of troops and more troops are on their way."
US President Joe Biden said on Tuesday that Russia had amassed more than 150,000 troops on the Ukrainian border.
But there has been hope that a diplomatic solution to the crisis is still possible, with Russian foreign minister Sergei Lavrov saying talks should be expanded and President Vladimir Putin adding that Russia does not want a war.
Russia repeated on Wednesday that they would return more troops and weapons to bases in what appeared to be an effort to quell fears that they are planning to invade Ukraine.
The Russian Defence Ministry released a video showing armoured vehicles moving across a bridge away from Crimea, the Black Sea peninsula that Russia annexed from Ukraine in 2014.
Russian fighter jets flew over Belarus on Wednesday and paratroopers held drills as part of war games.Belarusian Foreign Minister Vladimir Makei said that all Russian troops will leave the country after the drills wrap up this weekend.
Biden and UK Prime Minister Boris Johnson agreed on Monday that there
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