The Kremlin-backed broadcaster, formerly known as Russia Today, said earlier this week the US Department of Justice had given it until Monday to register its US operations as a foreign agent or see its head arrested and its accounts frozen.
"An attack on our media is an attack on freedom of speech," Putin told journalists at the APEC summit in Vietnam.
"They went the route of de-facto closure (of RT)," Putin said. "There will be a proper tit-for-tat response."
The uproar led the US Justice Department to demand RT to register its American operations as a "foreign agent" under the Foreign Agents Registration Act, which aims at lobbyists and lawyers representing foreign political interests.
More From This Section
RT said yesterday it would comply with the demands but would go to court to challenge the measure.
"We are disappointed, as they say in these situations," Putin said.
"There is not and cannot be any confirmation that our media was meddling," he said, adding that the money RT spent on ads was miniscule compared with the whole cost of the campaign.