WARSAW, Oct 15 - The risk that Russia could erode Western support for Ukraine through hybrid attacks, sabotage and disinformation campaigns is a key concern for Estonia, the Baltic nation's top diplomat said.

European officials have warned that Moscow is intensifying such attacks across the continent in an effort to sow opposition to the wide-ranging support that Ukraine's European neighbours and NATO provide to Kyiv to help it resist Russia's invasion.

"Russia is looking very carefully how we react. What is our political unity in practice," Foreign Minister Margus Tsahkna told Reuters in a brief interview on the sidelines of a conference in Warsaw.

"I think the Baltic states, Finland, Poland ... have prepared mentally for decades that Russia may commit different levels of attacks," he said. "But my main concern is that the Western part of European societies, they are not ready." The Kremlin consistently denies European allegations of drone attacks on land and at sea, cyberattacks, arson and other covert operations in NATO countries.

Tsahkna reiterated concerns that Moscow may step up hybrid efforts, with a likely focus on critical infrastructure and defence industry companies, to divide Western societies.

Ties between Ukraine and the United States have come under strain and opponents of aid to Ukraine have been gaining ground in Europe.

On Wednesday, Germany's far-right Alternative for Germany (AfD) and the small leftist BSW party joined forces to pass a symbolic motion in the state parliament of Saxony-Anhalt calling for an end to Berlin's military support for Ukraine.

In France, National Rally leader Marine Le Pen, who is leading in opinion polls ahead of next year's presidential vote, has said France can no longer afford to finance Ukraine.