An incident in which a young man declined to offer his seat and was slapped five times in the face by an irate husband in East China has provoked heated public discussion.

According to Youth Times, which learned of the incident from a passenger on the bus surnamed Liu, the young man was seated on a crowded bus in Hangzhou, Zhejiang province, about 1 pm on Thursday.

A young couple - a small, strongly built man and his wife carrying an infant - got on the bus and stood next to the man.

The driver asked passengers several times over the loudspeaker if someone would give up his seat for the woman and child, but to no avail.

After several stops, the woman found a seat in the back. The husband remained beside the young man, who according to the driver, was not in a seat designated for children, the elderly, infirm, or pregnant women.

Suddenly, the husband shouted at the man and slapped him in the face, knocking his glasses to the floor and making his nose bleed. From the back, the wife cursed the man. The man did not retaliate or speak.

Shortly after, the couple got off. Some passengers handed the young man tissues and picked up his glasses.

A photo provided by the passenger Liu shows the young man with a tissue stuffed in one nostril seated on the bus holding his broken glasses. His hands and nose are blood-stained.

Unlike in some similar cases, when the public were less sympathetic, many people have said they understand the young man's actions and have condemned the violence.

On Sina Weibo, China's answer to Twitter, the incident took center stage after a user posted that he was the young man's friend and that he was disabled.

The blogger continued that the young man had wanted to offer the woman his seat but could not because of his disability.

The incident has sparked heated public discussion.

"It is a voluntary matter, whether one offers his or her seat to others," said Wang Xiaoli, a postgraduate student in Hangzhou. "There's no obligation to do so and resorting to violence is overstepping the mark."

The Beijing Times commentator Li Liyan wrote that the violence was inexcusable.

"Because one doesn't offer a seat, hurling insults and getting violent? Such behavior is more uncivilized than not offering a seat. It betrays social morality and could be unlawful."

He Juanhong, a lawyer with Guangdong Xintong Law Firm, said it is a purely moral obligation to offer a seat to people in need if the seat is not designated for a special group. "People should only be encouraged, not forced, to offer the seat. Accusations should not be employed if others won't take the initiative to help."

wangzhenghua@chinadaily.com.cn