For countries once ruled from Moscow, US President Joe Biden's comments last week about seeking a possible "accommodation" between Russia and major NATO powers have had a chilling effect.

It was "a significant and important slip-up" that "sent very mixed messages to Russia", said Michal Baranowski, director of the Warsaw office of the German Marshall Fund, a think tank.

The White House has since rowed back on the remarks and emphasised the need for unity, even as Russia has listed demands including a guarantee that Ukraine will not join NATO and the withdrawal of NATO weaponry from countries bordering Russia.

For Baranowski, acceding to Russia's demands is unthinkable.

"You have zero guarantees that Russia would keep its promise of not escalating further... This is what major wars in Europe were made of, that kind of way of thinking," he said.

- 'Some form of accommodation' -

But Marcin Zaborowski, policy director at the Globsec think tank, said he believed there could be "some form of accommodation for Russian demands", particularly on NATO's presence in the region and arms sales to Ukraine.

"Things are happening which affect the region without the region taking part," he said.

After Biden's call with Russian President Vladimir Putin last week, several countries on NATO's eastern flank voiced concern.

Jakub Kumoch, an adviser to Polish President Andrzej Duda, said all members of the alliance should be involved in the diplomacy over Ukraine -- not just "a select group".

"That is what Russia would very much like -- a division of the alliance," he said.

Estonian Foreign Minister Eva-Maria Liimets said any concessions "would only lead to new pressures", while her Latvian counterpart Edgars Rinkevics said that "creating 'spheres of influence'... is impossible in today's world".

- Not 'behind our backs' -

Historical memories of the destructive effects of great power rivalry in the 19th and 20th centuries are still strong in a region where the Second World War began.

Baranowski said it would be unthinkable to return to a time when countries between western Europe and Russia were treated as "something to be agreed on" rather than stakeholders.

Biden sought to calm nerves last week by holding talks both with Ukrainian President Volodymyr Zelenski and with nine eastern NATO members.

Asta Skaisgiryte, an adviser to Lithuanian President Gitanas Nauseda, said Biden had emphasised that "nothing will be discussed behind our backs".

"President Biden also assured that additional assurance elements among these (eastern) NATO countries were possible, including additional capabilities," she said.

Nauseda and Duda, both of whom have emphasised the need for NATO to reinforce its presence in their countries, will meet with Zelensky in Ukraine next week for a summit.

Putin meanwhile has called for "immediate" talks with the United States and NATO over security guarantees and has presented Russia's proposals to a top US diplomat who visited Moscow this week.

Russia has long been concerned about NATO's eastward expansion and has accused Ukraine of breaching a ceasefire agreement with pro-Russian separatists in eastern Ukraine.

Putin has also accused the West of provoking tensions in the Black Sea, decrying US-led military exercises there.

- A 'recurring situation' -

Despite differences on how to respond to Russia, Wojciech Przybylski, editor-in-chief of Visegrad Insight, a think tank, said he saw greater unity between EU and NATO members.

"The positions are not always aligned... but there is a growing similarity in threat perception," he said.

But Zaborowski said: "I can't say I see much convergence" between countries that see Russia as a partner and those that view it as a threat or, like Germany, "somewhere in-between".

Ultimately, Przybylski said that Russia's current rhetoric may prove "counter-productive" to Moscow's goals by, for example, pushing Ukraine to make a more assertive bid for NATO membership.

"Russia are putting on the table a thing that wasn't there," he said.

In any case, he warned the situation was likely to persist since Russia is "getting attention that they have not had in the past".

"It will be a repetitive, recurring situation," he said.