The U.S. Federal Aviation Administration (FAA) on Tuesday said it was prepared to take action including the rerouting of Japan-bound flights if the nuclear crisis there worsened.

The Japanese government has already imposed flight restrictions to keep civil aviation flights away from the crippled Fukushima Daiichi nuclear reactor, which is now sending low levels of radiation toward Tokyo.

The FAA said in a statement that U.S. carriers are complying with the Japanese restrictions and added that there is currently no credible information to suggest a need for further steps.

"If the situation at Fukushima worsens and we see credible indications that radiological hazards to civil aviation exist beyond the flight restriction areas ... the FAA is prepared to take air traffic management measures, including the rerouting of air traffic," the statement said.

"If this scenario were to occur, we anticipate that the U.S. carriers and other operators flying in the affected airspace would revise their flight schedules."