Moscow said Friday that it was preparing a "judicial response" to official asset freezes overseas, after state accounts and property were reportedly blocked in Belgium and France over legal claims from former Yukos shareholders.

Moscow said Friday that it was preparing a "judicial response" to official asset freezes overseas, after state accounts and property were reportedly blocked in Belgium and France over legal claims from former Yukos shareholders.

"Russia is working on it. What our response will be -- time will tell," deputy foreign minister Vasily Nebenzya told Interfax news agency, adding that "whoever acts like this has to understand that there will be a counter reaction."

A representative of claimants from the defunct oil firm said Thursday that official accounts and buildings had been frozen in the two countries.

In Belgium, accounts of the Russian embassy in Brussels and representative offices at the European Union and NATO headquarters were among those affected, the Russian foreign ministry said.

Moscow summoned the Belgian ambassador to explain the move and threatened "reciprocal measures targeting Belgian assets in Russia".

The Belgian foreign ministry said the seizures had been conducted by bailiffs without the involvement of the Belgian government.

In France, accounts in around 40 banks were frozen along with eight or nine buildings, Tim Osborne, executive director of the main shareholder GML, told AFP.

There was no immediate confirmation of the asset freezes in France from officials in Moscow or Paris.