TOKYO - Despite public concern and raging opposition from both home and abroad, the Japanese government announced Tuesday it has decided to start releasing nuclear-contaminated wastewater from the crippled Fukushima Daiichi Nuclear Power Plant into the ocean on Thursday.

Despite pouring rain, hundreds of Japanese gathered on Tuesday morning in front of the Japanese prime minister's official residence to protest the government's irresponsible decision.

The ocean discharge which could last several decades is expected to commence Thursday, weather and sea conditions permitting, according to the controversial decision announced by Prime Minister Fumio Kishida following a ministerial meeting held on Tuesday morning.

Kishida claimed that the government will take full responsibility for the decision.

"No matter how the wastewater is 'treated', its nuclear-contaminated nature remains unchanged. All the Japanese government wants is to create a fait accompli with the ocean discharge," Hideki Taki, one of the rally's organizers, expressed extreme anger at the government's unilateral move to push forward with the discharge.

He emphasized that those against the discharge are determined to continue voicing their strong opposition and fighting with all their might.

For Yoshiko Furukawa, who used to live near the Fukushima Daiichi nuclear power plant and had been forced into long-term evacuation due to the nuclear accident, the prime minister's claim to take responsibility rang hollow to her. "He lacks the qualifications, authority, and right to assume such responsibility," she told Xinhua at the gathering.

Prior to Tuesday's announcement, Kishida visited the wastewater treatment facility at the plant on Sunday and met with the head of Japan's national fisheries federation on Monday in hopes of gaining an understanding.

"Our position has not changed, and we continue to be opposed to the ocean discharge," Masanobu Sakamoto, head of the National Federation of Fisheries Cooperative Associations said after the meeting.

Hit by a magnitude-9.0 earthquake and an ensuing tsunami on March 11, 2011, the plant suffered core meltdowns that released radiation, resulting in a level-7 nuclear accident, the highest on the International Nuclear and Radiological Event Scale.

The plant has been generating a massive amount of water tainted with radioactive substances from cooling down the nuclear fuel in the reactor buildings, which are now being stored in about 1,000 storage tanks.

The Fukushima plant has stored more than 1.3 million tons of nuclear-contaminated wastewater, and the discharge is planned to continue for more than 30 years, according to the Tokyo Electric Power Company (TEPCO), the operator of the plant.

In 2015, the Japanese government and TEPCO made an agreement with fisheries cooperative associations of both Fukushima prefecture and the nation that they would not proceed with any wastewater disposal "without the understanding of relevant parties".

"I had a faint hope that they would keep the promise, but eventually that was a lie," a 62-year-old fisherman from Iwaki City in Fukushima Prefecture was quoted by local media as saying.

Mizuho Fukushima, head of the Social Democratic Party, criticized the government for disregarding agreements made with stakeholders, arguing that the decision to proceed with the ocean discharge despite widespread opposition amounted to a "reckless act" by the government, trampling over the concerns of the majority.

A total of 88.1 percent surveyed expressed concerns over the government's plan to discharge treated radioactive wastewater into the ocean, as the disapproval rate of the Kishida-led cabinet rose to an eight-month high, according to the latest opinion poll conducted by the national news agency Kyodo.