Japan’s NHK says Tokyo has apologized for dumping radioactive contaminated water from the quake-crippled Fukushima Number One nuclear power plant into the Pacific Ocean without giving prior notice on the matter to neighboring countries.

During a news conference on Tuesday, a senior official of the Japan Nuclear and Industrial Safety Agency, Hidehiko Nishiyama, said Japan had no choice but to dump the contaminated water into the sea, given the urgency. However, he was quick to apologize for failing to inform neighboring countries on the matter.

Nishiyama said that Japan will, in the future, provide clear explanations on such decisions and respond to any questions from such nations.

The South Korean embassy in Japan conveyed to Japan’s Foreign Ministry on Monday its concerns over the discharge, saying that the water containing radioactive substances 100 times higher than the allowable level could cause an international legal dispute.