A damaged Japanese nuclear plant is suspected to be leaking radiation-contaminated water into the Pacific Ocean, Tokyo authorities were quoted as saying by news reports Thursday. The Nuclear Regulation Authority (NRA) said it is "highly suspected" that radioactive water at the Fukushima Daiichi Nuclear Power Station had seeped into the ground and contaminated the sea, the Kyodo News agency reported. "We must find the cause of the contamination and put the highest priority on implementing countermeasures," said Shunichi Tanaka, the head of the NRA. Plant operator Tokyo Electric Power Co said this week that levels of radioactive material in groundwater had risen sharply at the complex.