China said Tuesday it was evacuating its nationals from quake-hit parts of Japan and two airlines cut flights to the stricken country, while foreigners scrambled to leave from Tokyo's airports.

As food, water and power ran short for many Japan and a nuclear crisis worsened, Air China and Taiwan's EVA Airways reduced their flights into the ravaged country. Malaysia screened passengers from Japan for radiation.

German flag carrier Lufthansa said it was diverting all Tokyo-bound flights to the other Japanese cities of Nagoya and Osaka, both hundreds of kilometres (miles) west of the capital, at least until Sunday.

Lufthansa is also checking flights from Japan for radioactivity but has not found any traces so far, a spokesman said.

China said it was sending buses to evacuate its citizens from four disaster-hit areas including Fukushima, where two blasts rocked a nuclear power station Tuesday and radiation levels rose to dangerous levels.

Higher-than-normal radiation was detected in Tokyo Tuesday as Japan fought its atomic crisis, but a city official said it was not at harmful levels.

Other overseas nationals in Japan took matters into their own hands.

Student Kin Li, 18, returned home to Hong Kong from Tokyo because of the radiation fears.

"Things were so chaotic over there. There were long lines at the airport -- it was like a refugee camp," he told AFP at the Chinese territory's airport.

Li's mother said: "I was so worried and unhappy. I told my son studying would have to wait -- 'Safety first.' The situation is just heart-wrenching. I just wanted him home."

At Tokyo's Haneda airport, where long queues stretched from departure desks, French national Baptiste Chetcuti said: "I have a pregnant wife and a 10-year-old daughter, and we're here at Haneda airport. We don't have any return tickets yet, but we want to leave Japan -- whatever the price."

EVA Airways cancelled 14 flights scheduled to leave for Tokyo from Taiwan before the end of March and another five to Sapporo, a spokesman for the firm said, blaming cancellations by tourists.

All flights to Sendai, whose airport was flattened by the tsunami, were cancelled until June 30, he said.

Air China called off half of its six daily Beijing-Tokyo flights for Tuesday and Wednesday, and one of its three Shanghai-Tokyo flights for each of the two days, while flights to Sendai were on hold.

But the flag carrier said it had cut flights because of worries over aftershocks rather than radioactive contamination.

"We have cancelled some of the flights from China for safety reasons. But most flights remain normal," Air China spokeswoman Zhu Mei told AFP.

"The cancelled fights were those scheduled to stay one night at Japan airports. The planes could face danger in the event of aftershocks."

Lufthansa also said the diversions were made "for different reasons" than fears of radioactivity, with the spokesman citing problems reprovisioning planes in Tokyo and ground transportation headaches for passengers.

Malaysia's airports authority said it was checking passengers for radioactive contamination as they came off direct flights from Japan. Thai Airways said it had told its cabin crew on flights to Tokyo not to stay overnight in Japan to reduce the risks from radiation and aftershocks.

Countries including Australia and Thailand have urged their nationals not to go near the stricken plant and to reconsider travel to other areas affected by Friday's 9.0-magnitude quake and subsequent tsunami.

Before the quake Japan's government set a long-term target of attracting 30 million overseas visitors a year. Over 600,000 overseas nationals were working in Japan as of 2009, according to the labour ministry.

burs-je/sls