Since the conflict in Ukraine, Western countries have introduced a barrage of sanctions against Moscow, blocking its banks from making international payments and freezing Russian assets abroad.

According to the Kremlin, more than $16 billion worth of foreign investments belonging to Russian citizens are now stuck abroad.

In response, Russia locked some assets belonging to foreign investors and companies in its country in so-called "Type-C" accounts.

According to the decree, Russian residents will be able to exchange their blocked assets abroad up to a value of 100,000 rubles (around $1,000) with funds from these accounts using a voluntary mechanism.

The owner of the Type-C account, which is nominally a foreign company, will then have the option of receiving the foreign share previously owned by the Russian investor abroad.

But there is no guarantee that foreign clearing houses Euroclear or Clearstream, which handle the exchange of shares, will co-operate.

Since the conflict in Ukraine began in February last year, dozens of Western companies have pulled out of Russia or sold their assets there to avoid falling foul of sanctions.