The water level in a spent nuclear fuel pond at Japan's blasts-ridden Fukushima No. 1 plant has dropped, overheating the container of the No. 3 reactor, The Mainichi Daily said on Thursday.
It warned that if no effective countermeasures are implemented, the fuel will melt which could result in a radiation leak.
Up to 64 tons of water was dumped by helicopters and fire trucks on the No. 3 unit, Kyodo said earlier in the day.
However, high levels of radiation prevent police from using water cannons to douse the overheated reactor. The radiation level at the 3rd reactor increased to 4,000 microsieverts per hour from 3,700 microsieverts with a normal radiation level within 0.05 - 0.2 microsieverts.
The International Atomic Energy Agency said at least 20 people were exposed to radiation and 25 were injured while tackling the consequences of the blasts at the plant.
The government's Nuclear and Industrial Safety Agency said white smoke was billowing from the No. 2 unit, suggesting that a spent nuclear fuel pool in the facility may also be boiling.
The buildings housing the No. 1, No. 3 and No. 4 reactors have been severely damaged by apparent hydrogen blasts, and the No. 2 reactor's containment vessel suffered damage to its pressure-suppression chamber at the bottom.
A series of blasts and fires damaged four of Fukushima's six reactors after a 9.0-magnitude earthquake struck off the northeast coast of Japan last week, sparking a powerful tsunami and killing thousands.
RUSSIA WILLING TO HELP
Russia is ready to help Japan extinguish fires at the Fukushima Nuclear Power Plant, Foreign Ministry spokesman Alexander Lukashevich said on Thursday.
"We confirm Russia's readiness to render any additional assistance to the Japanese side in dealing with the aftermath of the NPP accidents, including putting out fires," Lukashevich said.
The death toll from the disaster has risen to 5,429 people and 9,594 are listed as missing, police said.
On Friday, helicopters will continue attempts to cool Fukushima's reactors with water, the Japanese news agency Kyodo said.
FOREIGN CITIZENS FLEE JAPAN AS RADIATION THREAT MOUNTS
Many countries continue evacuating their nationals from Japan amid mounting fears over possible radiation leakage.
Colombian and Mexican authorities have sent several planes to Tokyo to return their nationals.
Spain is considering organizing additional flights to Japan.
Great Britain has dispatched charter flights with tickets costing $969 from Tokyo to Hong Kong.
Several European countries, including the Czech Republic, France, Poland and Bulgaria have already evacuated their citizens from Japan.
The Russian Foreign Ministry said there was no mass evacuation of Russians. Family members of those working in the Russian Embassy in Tokyo will be evacuated.
RUSSIAN SHIPS LEAVE JAPANESE PORTS
Oil tankers of Russia's largest shipping company Sovkomflot left Japanese waters after the company's authorities ordered them to "spread out," Sovkomflot's deputy head Vladimir Mednikov said.
Sovkomflot is not planning to increase the number of ships to deliver additional oil and liquefied natural gas to Japan.
"The main thing for us is our people and the ships' security. If a vessel is exposed to radiation, there is nothing we can do with it. It will not enter any single port, it will not be sold even for scrap metal," Mednikov said.
MOSCOW, March 17 (RIA Novosti)
