The condition of four reactors at the troubled Fukushima Daiichi nuclear power plant was improving.?

Pressure levels inside the containment vessel of the No. 3 reactor at the stricken Fukushima nuclear power plant are stabilizing, Japan's nuclear safety agency said Sunday afternoon.

This may prompt the power company in charge of the plant to delay?actions to release steam from the reactor.

Tokyo Electric Power Co. (Tepco), the operator of the troubled plant, said the pressure within the reactor had been stabilizing so?they?wouldn't conduct ventilation for a while, Japanese media reported.

Earlier in the day, Tepco planned to open valves at the reactor to reduce pressure levels, which was feared to lead to a release of radioactive steam.

According to Japan's defense ministry, it succeeded in putting water into the No. 4 reactor Sunday morning.

About 80 tons of water was believed to be shot into the reactor's spent fuel pool.

On Saturday, Japanese Defense Minister Toshimi Kitazawa said the situation of No.1 to No. 4 reactors was "more stable than expected" after the Self-Defense Force and firefighting personnel shot water over the No. 3 reactor.

Japan's National Police Agency said Sunday that 8,133 people are confirmed dead and 12,272 remain missing after the 9.0-magnitude earthquake and ensuing tsunami struck Japan on March 11.