Japanese authorities trying to stave off meltdowns at an earthquake-damaged nuclear power plant reported more grim news this morning as radiation levels soared following another explosion at an overheating reactor.

The risk of further releases of radioactive material from the Fukushima Daiichi nuclear power plant remains "very high," Japanese Prime Minister Naoto Kan said. In addition to an explosion at the No. 2 reactor, the building housing the No. 4 unit - which had been shut down before Friday's earthquake - was burning this morning, Chief Cabinet Secretary Yukio Edano announced.

The plant's owners, the Tokyo Electric Power Company, evacuated all but about 50 of their workers from the plant following this morning’s explosion at the No. 2 reactor. Radiation levels at the plant have increased to "levels that can impact human health," Edano said - between 100 and 400 millisieverts, or as much as 160 times higher than the average dose of radiation a typical person receives from natural sources in a year.

Evacuations have already been ordered for anyone living within 20 kilometers (12.5 miles) of the plant. , and Edano said anyone between 20 and 30 kilometers (between 12.5-18.6 miles)

Meanwhile the death toll from Friday's 9.0-magnitude earthquake and subsequent tsunami has risen to 2,475, authorities said earlier today. At least 3,118 people were missing and 1,889 injured, according to the National Police Agency Emergency Disaster Headquarters. (CNN)

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Courtesy BBC