On Wednesday, Ukrainian authorities shut down an independent radio station, Radio Kontynent while it was on the air and confiscated its transmitter.
On Feb. 17 Ukrainian programs of Radio Free Europe and Radio Liberty were taken off the air in cities across Ukraine.
"The United States views (such actions) with grave concern" and considered them "an assault on democracy," State Department spokesman Richard Boucher told reporters in Washington.
"We call on the Ukrainian leadership to act immediately to allow Radio Kontynent to resume broadcasting and to refrain from erecting further obstacles to ... international radio broadcasts," he said.
"Ukrainian authorities must cease their ongoing campaign against independent media."