Japanese engineers have connected four of the reactors at the crippled Fukushima nuclear power plant to electricity cables, but will restore the electricity supply only after a detailed inspection of equipment, the Kyodo news agency reported on Monday, according to RIA Novosti.
The United Nations nuclear agency said earlier on Monday that smoke and vapor rising from the earthquake-damaged plant had become less intense.
The electricity supply, which could take up to three days to be restored, will run an automated cooling system in reactors and pools containing spent nuclear fuel.
Tokyo Electric Power Co. also expects to lay power cables to the other two reactors on Tuesday.
The death toll from a powerful earthquake and tsunami that hit Japan 10 days ago has risen to 8,450, with 12,931 people missing. The disaster triggered a number of explosions at the Fukushima Nuclear Power Plant, spreading fears of a large-scale radioactive contamination.
Heavy rain has heightened fears of radiation and forced Prime Minister Naoto Kan to cancel a visit to the plant.
People living near the plant have been told not to drink tap water due to high levels of radioactive iodine. Traces were also detected in tap water in Tokyo.
On Saturday and Sunday spinach and milk produced near the plant was found to have higher than legal radiation levels. The sale of some products was halted over possible health risks.
The World Health Organization described on Monday the threat from food contamination as "serious," Reuters reported.
Around 3,400 Russians have been evacuated from Japan by the Russian Emergencies Ministry since the disaster struck on March 11. Emergencies Ministry planes are still running between Tokyo and Vladivostok, although the numbers of Russian nationals trying to leave have decreased significantly in the past few days.