Tokyo has recently voiced concerns over the safety of its citizens in China, after a Japanese schoolboy was fatally stabbed in neighbouring Shenzhen in September.

In a safety alert sent out early Tuesday about the car ramming, the embassy said it had no information that any Japanese citizens had been involved, but noted that there had been a series of other attacks in China recently.

Japanese residents of China should "respect local customs, be aware of surroundings and be mindful of what they do and say when interacting with Chinese people", it read.

They should "refrain from going outside alone during nighttime", and even during the day, avoid "speaking loudly in Japanese and avoid provocative, attention-drawing behaviour such as being loud in groups".

When going out, they should "pay close attention to their surroundings, and be on high alert in crowded places like squares".

Relations between Japan and China have worsened as Beijing builds up its military capacity in the region, and as Japan boosts security ties with the United States and its allies.

The stabbing of the 10-year-old schoolboy in September saw them strain further, with Tokyo demanding an explanation from Beijing and that the safety of Japanese citizens was ensured.

China has seen a spate of violent public attacks in recent months.

A man killed three people and wounded 15 in a knife attack at a supermarket in the Chinese megacity of Shanghai in October.

And in July, police said a vehicle crashed into pedestrians in the central city of Changsha, killing eight.