Brussels has warned U.S. companies that their assets in Europe could be seized in retaliation to claims targeting EU firms over property confiscated in Cuba during its 1959 revolution, Bloomberg News reported.

The Trump administration fully enforced a law, effective May 2, that allows U.S. citizens to seek damages in federal courts from businesses that have operated using their former property in Cuba. The EU is concerned that the move could lead to a series of lawsuits against foreign companies.

In a letter to the U.S. Chamber of Commerce, the European Commission said European companies are legally allowed to file counterclaims in EU courts against U.S. claimants and recover any damages from them.

"Such damages could be recovered through the seizure of assets in the EU held by U.S. claimants" or their representatives, including shares in EU companies, the EU reportedly said in the letter.

In April, EU officials including Trade Commissioner Cecilia Malmström warned that Brussels would be compelled "to use all means at its disposal" if Washington completely implemented Title III of the 1996 Helms-Burton Act, including filing a case at the World Trade Organization.