The number of those killed or missing after Friday`s massive earthquake and tsunami in northeastern Japan has topped 5,000, Kyodo news reported on Monday citing police, according to RIA Novosti.
Officials warn the death toll in the Miyagi prefecture alone could rise beyond 10,000 people.
The total number of confirmed deaths now stands at 1,833.
Russia, the United States and other countries have sent in rescue teams to join a huge relief effort in the quake-ravaged island nation.
Tens of thousands of people have been evacuated from the area around Fukushima Nuclear Power Plant, where a blast hit reactor No. 3 on Monday morning following an explosion on Saturday.
At least 11 people were reported injured in the explosion. Officials say the reactor resisted the blast and played down any health risk.
An explosion occurred in reactor No. 1 on Saturday.
The plant`s operator, Tokyo Electric Power Co., said the cooling system at reactor No. 2 has failed, but seawater is still being pumped into the reactors in a bid to cool them down.