Radioactive water leaking directly from Japan’s nuclear plant (VIDEO)

Highly radioactive water is leaking from Japan's stricken nuclear power plant and into the sea, nuclear safety officials said Saturday.

The water is coming from a newly discovered eight-inch wide crack in a containment pit on the edge of the Fukushima Dai-ichi nuclear plant and seeping directly into the Pacific Ocean, said Japan Nuclear and Industrial Safety Agency spokesman Hidehiko Nishiyama, as reported in the AP.

Long-term risk of cancer can be increased by exposure to 500 millisieverts of radioactivity over a short period of time; tests of the air above the crack revealed 1,000 millisieverts of radioactivity an hour, it states.

However, nuclear safety experts told the AP that the Pacific Ocean can quickly dilute even large amounts of radiation.

This is the first identified direct leak of such high levels of radiation into the sea, reports the New York Times.

The operator of the plant, Tokyo Electric Power Co., plans on pouring concrete into the pit to try to seal the crack and stop the leak, BBC reports.

"With radiation levels rising in the seawater near the plant, we have been trying to confirm the reason why, and in that context, this could be one source," Hidehiko Nishiyama, deputy director-general of the Nuclear and Industrial Safety Agency, said at a news conference. "There could be other similar cracks in the area, and we must find them as quickly as possible."

This comes after radiation was found in groundwater just outside the stricken nuclear plant at 10,000 times the normal limit.

Japanese officials and engineers have been struggling to bring the plant under control since a 9.0 earthquake and tsunami devastated much of Japan on March 11 and knocked out the plant's cooling systems. The disaster has left nearly 28,000 people dead or missing.

Japanese Prime Minister Naoto Kan made his first ground visit to the disaster zone Saturday, visiting Rikuzentakata and trying to assure those affected that the government will support them.

However, some survivors felt the trip — three weeks after the disaster struck — was too late.

"The timing of his visit is too late," Ryoko Otsubo told BBC. "I wish he had visited this place earlier. I wanted him to see the piles of debris where there were no roads through – now the roads are cleaned."

On Friday, U.S. Energy Secretary Steven Chu said reactor No. 2 at the plant had suffered approximately a 33 percent meltdown and said that reactor No. 1 had suffered severe damage to about 70 percent of its core, the New York Times reports.

— Hanna Ingber Win