BEIJING (Reuters) - Some Japanese companies in China have offered to send their staff and their families back home after a 10-year-old Japanese boy was fatally stabbed in the Chinese city of Shenzhen, a Japanese executive and employees of Japanese firms in Beijing said on Friday.

Japan's ambassador to Beijing has asked for more security for Japanese nationals in China after a 10-year-old Japanese boy was killed this week in a knife attack that was the second to target school students.

Japan’s prime minister has demanded an explanation from Beijing over the fatal stabbing of a schoolboy in the second knife attack on Japanese children in China in recent months. The 10-year-old boy was stabbed by a man on his way to class Wednesday about 200 meters (650 feet) from the gates of the Japanese school in the southern city of Shenzhen,