Highly radioactive water has been found at a second reactor at a crippled nuclear power station in Japan, the plant’s operator said, as fears of contamination escalated two weeks after a huge earthquake and tsunami battered the complex.

Underscoring growing international concern about nuclear power raised by the accident in northeast Japan, U.N. Secretary-General Ban Ki-moon said in a statement it was time to reassess the international nuclear safety regime.

Earlier, Japanese Prime Minister Naoto Kan, making his first public statement on the crisis in a week, said the situation at the Fukushima nuclear complex, 240 km (150 miles) north of Tokyo, was “nowhere near” being resolved.