Russia said it will retaliate next week against American media after the U.S. government ordered state broadcaster RT to register as a foreign agent, following accusations it interfered in last year’s presidential elections.

Officials didn’t specify what measures would be taken. Foreign Ministry spokeswoman Maria Zakharova said Thursday that “practical implementation” of steps in response to the U.S. move will begin next week, according to state media. Russian authorities have repeatedly said their retaliation will mirror any restrictions imposed by the U.S. The foreign-agent label, which applies to several state-owned outlets operating in the U.S. including Japan’s NHK and the China Daily newspaper, requires disclosure of the media organization’s foreign funding.

The editor-in-chief of RT, Margarita Simonyan, said on the broadcaster’s website that it has no choice but to comply with the U.S. Justice Department’s demand to register as a foreign agent by a final deadline of Monday. Otherwise, the head of the channel’s U.S. subsidiary would face detention and its bank accounts would be frozen, she said. “This demand violates U.S. law and we intend to appeal it in U.S. courts.”

Tensions have risen steadily between the U.S. and Russia since Donald Trump took office early this year despite the president’s campaign promises of better relations. The two former Cold War rivals have targeted each other in a bitter diplomatic tit-for-tat after America toughened sanctions on Russia for alleged election meddling.

The U.S. Congress is investigating RT’s role in the 2016 election, as well as possible influence by state-owned Sputnik news service. The Russian authorities have signaled that CNN and Radio Liberty could be among those targeted in response to the action against RT.