China has renewed its criticism of Japan's decision to release treated radioactive water from the wrecked Fukushima nuclear plant into the Pacific Ocean.
Foreign Ministry spokesperson Zhao Lijian called the decision to begin releasing the water in about two years a money-saving measure that is "extremely irresponsible".
Zhao also rejected Japanese complaints over a tweet he earlier sent criticising Japan's decision with a picture of a famous Japanese print of a massive wave.
He said it was hypocritical of Japan not to allow others to criticise when it had failed to consider the concerns of its neighbours.
"Certain Japanese officials have been playing deaf and dumb. Then why are they so angry about this image?" Zhao said at a daily briefing on Wednesday.
"The Japanese side should recognise its responsibility, fulfil its international obligations and revoke its wrong decision."
Japanese Foreign Minister Toshimitsu Motegi on Tuesday said Japan had protested and demanded removal of the tweet. Ministry spokesman Tomoyuki Yoshida on Wednesday said the tweet lacked scientific basis.
"Contrary to Japan's sincere effort to respond to the international society with high levels of transparency, (the tweet) is not based on any scientific evidence whatsoever, it is one-sided and it incites emotions, and it is extremely regrettable," he said.
Japan's decision to release the water had long been anticipated, but was delayed by safety concerns and protests.
Cabinet ministers endorsed it as the best option, although it is fiercely opposed by fishermen, residents and Japan's neighbours.
The water has been used to cool melted fuel at the nuclear plant damaged by a massive 2011 earthquake and tsunami, but the tanks where it is being stored will be full next year.
Also Wednesday, Japan said its military has raised caution levels around uninhabited East China Sea islands that it controls but are also claimed by Beijing after six Chinese warships passed near the area and a reconnaissance helicopter flew toward it.