The damaged barrier is carried away from the South Urumqi Road entrance of the consulate in Shanghai late on Thursday night. [Provided to China Daily]

The US consulate in Shanghai was open for business as usual on Friday after a car rammed into a barricade at the gate of the compound, injuring a sentry, the previous night.

"All mission personnel at the consulate general have been accounted for and the consulate general is expected to be open for business as usual today, the 13th," a spokesman said.

On Friday, the consulate was guarded by four sentries as usual, and a police car was parked across the entrance.

Liu Daojie, the driver involved in the crash, claimed someone had been attempting to kill him for a month, and he had "tried to provoke an incident to draw attention".

Shanghai police said Liu, 35, was driving a black Toyota sedan registered in Fujian province along South Urumqi Road. The car suddenly veered right and hit the guardrail at the consulate's side entrance at 9:43 pm. Police and consulate sentries took Liu into custody.

Sun Tao, a 20-year-old guard, was injured as he tried to intercept the car. He was taken to the nearby Huashan Hospital, and pictures posted on social media platforms show a bloodstain at the site.

Surveillance camera footage that was posted online by CCTV shows the Toyota moving slowly along the road before it suddenly speeds up, turns right and crashes into the barricade.

Sun can be seen as he is thrown to the side by the impact, and other sentries and police officers then try to smash the car's windows with sticks.

The police said Liu, a native of Sanming in Fujian, claimed he ran a large company in the province and believed someone wanted to kill him.

A police statement quoted him as saying, "I drove from Hangzhou to Shanghai today, and saw the place is guarded by armed police, so I crashed my car into it." The police said Liu appeared confused and spoke incoherently, but an initial investigation indicated that he was not drunk or under the influence of drugs when the crash occurred.

Officers contacted Liu's wife, surnamed Qian, at a hotel in Hangzhou, the capital of Zhejiang province, early on Friday morning.

She said Liu believed someone had been hunting him for a month, and as a result he was afraid to leave their house.

He had sought medical help, accompanied by his wife, and a doctor had tried to help him think more clearly.

On Thursday morning Liu drove Qian and their daughter from their home to Hangzhou. After checking into a hotel at 5 pm, he told her he was going out to meet a client and did not return.