China's tourism authorities on Sunday reminded people to be prudent before travelling to Japan and warned Chinese tourists in Japan about aftershocks.

The National Tourism Administration (NTA) suggested tourists to avoid visiting Fukushima and Sendai where quake damages are most severe.

By Sunday noon, 189 Chinese tour groups, with a total of 4,683 Chinese tourists in Japan, had been confirmed to be safe with no death or injury reported, said the NTA based on information from 26 province-level tourism authorities.

The NTA has activated the emergency response system and issued a travel alert concerning Japan and countries along the Pacific Rim, after a devastating 9-magnitude earthquake jolted Japan's eastern coast Friday.

The NTA has also called for travel agencies to protect the security of Chinese tourists in Japan and keep in touch with the Chinese Foreign Ministry and Chinese embassy and consulates in Japan, as well as China's tourism authorities.

The NTA also urged travel agencies hosting in-bound tourists to assist Japanese embassy and consulates in China to provide help to Japanese tourists in China.

Chinese tour agencies had started to bring back tourists from the quake-hit Japan and many trips had been called off.

China CYTS Tours, one of China's major travel agencies, had promised a full refund for trip cancellation and offered to bear the extra expense for tourist protection in disasters and unrest.

A massive 9-magnitude earthquake struck off the east coast of Japan's main Honshu Island at 1:46 p.m. Beijing Time Friday, which had triggered huge tsunami along Japan's Pacific coast and caused hundreds of deaths and catastrophic damage.