Police have confirmed that at least seven young women have been stabbed by the same man in a series of frightening assaults across two provinces.

However, officers have refuted widespread online claims that the assailant is targeting young women who wear red.

Of the seven stabbings that have been reported to police, five were in Guantao county in Handan city, North China's Hebei province. The other two happened in neighboring Guanxian county, Shandong province.

None of the women have died, said a police officer surnamed Zhang from Guantao county.

Investigators are satisfied that the same man was responsible for all of the incidents, Zhang said.

Police in Hebei are working with their colleagues in Shandong and urging residents to share any information they may have.

"The cases are still under investigation," Zhang told China Daily on Tuesday.

"If there is any progress, it will be made known to the public as soon as possible but people should not believe the online postings, which may be exaggerating the information."

In recent days, online posts have said "a metamorphosis killer" had stabbed women aged around 25 who wore red clothes.

The postings also claimed that the stabbings had resulted in three deaths. The postings said at least 17 women had been attacked.

The online comments helped feed panic in the area and many young women are refusing to step outside, especially in red clothes.

A female shopkeeper surnamed Li in Guantao county told Hebei Youth Daily she had heard that the attacker was furious at women following his divorce.

Pointing at her own red coat, Li said she had to wear it in her shop to keep warm but would take it off if she had to venture out.

"It's so horrible. I don't dare to go out in the dark night," she told the newspaper.

A local restaurant owner said he had been meeting his daughter from school each day.

"As long as the attacker is at large, I am not at ease," he said. "It's better to be careful."

Police, however, said not all of the women who were attacked wore red.

One female victim, surnamed Jiao, a nurse at a local hospital in Hebei province, was stabbed in the lung on the afternoon of March 28.

She said she was not wearing red that day.

Jiao, who is being treated in hospital, told the newspaper she was stabbed while crossing a bridge on her electric bike on her way to work. Her attacker caught up to her on a motorcycle.

Experts said there are all sorts of reasons why someone may suddenly start to commit such a series of crimes.

"A suspect's violent behavior may be in connection to his family background, living environment, personality and educational level," said Li Meijin, a professor in crime psychology at the Chinese People's Public Security University.

She told China Daily on Tuesday that the time of the year could also be a factor.

"People are more inclined to be emotionally unstable during the spring, which may lead to irrational behavior."

Women are being urged to be on guard and travel in groups if they are in quiet areas.