CHENGDU - Four people have been killed and 11 others were injured when a knife-wielding man hacked passengers on a bus on Sunday night in Southwest China's Sichuan province, local police said.

The bus camera shows that the suspect suddenly took out a knife at 9:16 pm and started to stab the passengers on the No 42 bus running through the downtown Chengdu, capital city of Sichuan, the city's public security office told Xinhua on Monday.

The man, surnamed Li, got off the bus soon and continued attacking people on the street before police opened fire and subdued him.

China Central Television (CCTV) said earlier a 10-year-old girl was severely wounded.

According to Chengdu police's initial investigation, the 41-year-old suspect is from Jintang county to the northeast of Chengdu city. He told police that he has worked as migrant worker elsewhere and has financial disputes with his family members.

Li left Xichang city in southwest Sichuan province last Thursday, went home in Jintang on Saturday, and arrived in Chengdu on Sunday noon, said the police.

A further investigation into the case in underway.

Within a two-week period, the country has witnessed several similar incidents in which suspects have attacked innocent passers-by.

On Aug 19, a knife-wielding man surnamed Zhou, killed three and injured 12 in Central China's Henan province, including a ten-month-old baby and a ten-year-old boy.

In a separate case on Aug 16 in Wuhan city, capital of Central China's Hubei province, a man with a knife injured five people and committed suicide by jumping off the fifth floor of a shopping-mall.

The Ministry of Public Security vowed all-out efforts to ensure public safety on July 25.

Chinese police said in a statement issued after a national teleconference on tackling public order offenses that violent crimes will be "resolutely punished."

The police will always "maintain high vigilance against terrorism, violent crimes and crimes involving guns or explosives, deal with problems affecting social stability and those complained most about by people, and eliminate various safety risks," said the statement.