Police have detained a man who allegedly killed at least three children in a kindergarten knife attack Tuesday in east China's Zibo City, Shandong Province, said a statement from the city government Wednesday.

Fang Jiantang, 26, self-employed, who was detained within hours of the attack, had admitted to police that he was responsible, said the statement.

Three children died at the scene, while three other children and four teachers were injured and taken to hospital, it said.

The conditions of two teachers were described as serious and the others were all stable, the statement said.

Fang said he had used a 60-centimeter long knife in the attack and police had found the murder weapon, said the statement.

The motive of the attack was not immediately known.

The investigation is continuing.