Knife-wielding assailants attacked civilians on a street in the central Chinese city of Changsha on Friday morning, state news agency Xinhua said, citing local authorities.
Xinhua said its reporters saw at least one body lying on the ground at the scene.
Photos on microblogs showed at least four bodies on a street outside a school and police taking a suspect into custody. The authenticity of the photos could not be immediately confirmed.
Xinhua did not make clear who was responsible for the attack in the city, capital of Hunan province.
The incident happened just two weeks after a deadly stabbing attack at a Chinese train station in the southwestern city of Kunming which killed 29 people and injured about 140.
The government blamed that attack on militants from the western region of Xinjiang, home to a large Muslim Uighur minority. Many Uighurs say they are infuriated by Chinese curbs on their culture and religion, though the government says they are given wide freedoms.