The Kremlin is preparing measures to retaliate against the U.S. for the seizure of two Russian diplomatic compounds in the U.S. last December by the Obama administration, said Reuters on Wednesday.

Russian foreign ministry spokeswoman Maria Zakharova said, “Retaliatory measures are being prepared. As you understand, such a decision on the issue won’t be made only by the foreign ministry.”

In December, the U.S. raided and seized two Russian compounds, one near New York City and one near Maryland’s eastern shore. Then-President Barack Obama’s administration expelled 35 Russian nationals from the U.S. on suspicion that they were instrumental to the Russian effort to meddle in the 2016 election.

Reuters said that the Russian newspaper Kommersant warned in June that the Kremlin was contemplating seizing corresponding U.S. properties in Moscow, one of which is the location of an Anglo-American school. Russia has reportedly given the U.S. until July to return the seized properties.