Following are main developments after a massive earthquake and tsunami devastated northeast Japan and crippled a nuclear power station, raising the risk of an uncontrolled radiation leak.

• Tokyo Electric Power (TEPCO), operator of the stricken plant, has begun paying "condolence money" to nearby local governments to aid people evacuated because of the crisis.

• TEPCO will begin making separate compensation payments to victims, Yomiuri newspaper said on Tuesday, but the company said nothing had been decided on such payments.

• Radioactive iodine of up to 4,800 times the legal limit has been recorded in the sea near the plant. Caesium was found at levels above safety limits in tiny "kounago" fish in waters off Ibaraki Prefecture, south of Fukushima, local media reported.

• Iodine-131 in the water by the sluice gate of reactor No. 2 hit a high on April 2 of 7.5 million times the legal limit. It fell to 5 million times the legal limit on Monday.

• Japan has asked Russia to send a floating radiation treatment plant, used to decommission nuclear submarines, which will solidify contaminated liquid waste from the Fukushima Daiichi plant, Russian media reported.

• TEPCO is releasing into the sea 11,500 ton of contaminated water from the plant to free up more storage space for water with much higher levels of radioactivity.

• A Japanese official said Tuesday the effort to fill a crack in the concrete pit of the complex's reactor No. 2 with sawdust, newspapers with polymers and cement does not seem to be working. Through the crack, radioactive water has been seeping into the sea.

• Japan has warned it could take months to stop radiation leaking from the nuclear plant.

• Authorities do not plan to expand the evacuation zone around the plant, a senior nuclear official said. The government created a 20-km (12-mile) evacuation zone around the site after the earthquake and tsunami.

• TEPCO has said it will scrap at least four reactors once they are under control, but this could take years or even decades.

• A total of 12,087 people were confirmed dead by Japan's National Police Agency, while 15,552 are missing. A total of 167,700 households were without electricity and at least 200,000 without running water.

• Estimated cost of damage to top $300 billion, making it the world's costliest natural disaster. The 1995 Kobe quake cost $100 billion while Hurricane Katrina in 2005 caused $81 billion in damage.