Another policeman who was injured in a knife attack here died of his injuries on Wednesday, bringing the death toll from the incident to six.

The suspect, surnamed Yang, stabbed a security guard at a police branch in the Zhabei district of Shanghai on Tuesday morning with a knife, and then charged into the building and attacked nine officers on four floors.

Five police officers died of their injuries on Tuesday and the others were hospitalized.

The Shanghai Public Security Bureau said it was the worst assault on the police in the history of the city.

Yang, 28, an unemployed Beijing native, went to the gate of the police branch with a knife, a hammer, Molotov cocktails and other weapons at about 9:40 a.m. on Tuesday.

He ignited eight Molotov cocktails and threw them at the gate, starting his rampage. The security guards tried to stop him, but he stabbed them and then began his attacks on the police.

He was apprehended by police at the scene and detained.

Shanghai police are still investigating the cause of the assault.

The Chinese Ministry of Public Security has sent its condolences to the families of the deceased.