BEIJING / TOKYO - Japan is likely to adjust its security policy to pay more attention to non-traditional security threats as a result of its natural disasters, said analysts, as Japanese officials apologized for the release of "not credible" radiation figures from its stricken nuclear complex.

The latest disasters have reminded the ruling Democratic Party of Japan (DPJ) that in a country frequented by natural disasters, more attention should be paid to non-traditional security threats, said Yang Bojiang, a professor at China's University of International Relations.

"An emphasis on non-traditional security threats will improve the DPJ's security outlook and promote its security cooperation with China and other surrounding countries", Yang said on Sunday in Beijing at the release of the Blue Book of Japan: Annual Report on Development of Japan (2011).

The book, the third in a series written by Chinese scholars specializing in Japanese studies, deals with key changes in Japanese politics, diplomacy, security, economy, society and culture in 2010, especially the latest developments in Sino-Japanese relations.

"Sino-Japanese relations were tense in 2010" following the Diaoyu Islands incident on Sept 7, 2009, it noted.

Yang, author of the chapter on the DPJ's security policy, said after the natural disasters that hit Japan on March 11, there is an opportunity for Sino-Japanese relations, but the lack of strategic trust remains an obstacle.

Shortly after the magnitude-9 earthquake and ensuing tsunami, China had prepared to send a rescue team of more than 100 to Japan, but the Japanese government only accepted a 15-strong team, the Southern Metropolitan Daily said.

"China made the utmost efforts to offer aid, but Japan is too cautious," said Li Wei, head of the Institute of Japanese Studies of the Chinese Academy of Social Sciences and chief compiler of the book.

At the Fukushima Daiichi nuclear complex, emergency workers struggling to pump contaminated water from the complex fled from one of the troubled reactors on Sunday after reporting a huge increase in radioactivity.

The workers fled the No 2 reactor when a reading showed radiation levels had reached 10 million times higher than normal in the reactor's cooling system.

On Sunday night, however, plant operators said that while the water was contaminated with radiation, the extremely high reading was a mistake.

"The number is not credible," said Tokyo Electric Power Co spokesman Takashi Kurita. "We are very sorry."

He said new samples were being taken, but did not know when the results would be announced.

The situation came as officials acknowledged there was radioactive water in all four of the complex's most troubled reactors, and as airborne radiation in the No 2 reactor measured 1,000 millisieverts per hour - four times the limit deemed safe by the government.

Two of the plant's six reactors are now deemed as safe but the other four are volatile, occasionally emitting steam and smoke.

Meanwhile, a magnitude-6.5 earthquake shook eastern Japan on Monday morning, the United States Geological Survey reported, prompting Japan to issue a tsunami alert.

There were no immediate reports of damage or injuries, but the Japan Meteorological Agency said a tsunami of up to half a meter may wash into Miyagi Prefecture. The tsunami alert was localized to Japan.

The latest quake was measured at 7:23 am on Monday, Japan time, near the east coast of Honshu. It was 5.9 kilometers deep.

Just outside the coastal nuclear plant, radioactivity in seawater tested about 1,250 times higher than normal last week - but that number had climbed to 1,850 times normal by the weekend.

Hidehiko Nishiyama, a nuclear safety official, said the area is not a source of seafood and that the contamination posed no immediate threat to human health.

Experts with the International Atomic Energy Agency said the ocean would quickly dilute the worst contamination.

Reuters and Associated Press contributed to this story.

China Daily