Prominent Chinese lawyer Gao Zhisheng has said that a car tried to run him over as he returned to his home in Beijing earlier this week.
Mr Gao is well known for handling politically sensitive cases
Mr Gao has defended several clients who claim to have been unfairly treated by the authorities.
He said he was used to being followed, but this time a car in front of him suddenly braked, and when he got out to investigate it tried to run him over.
He told the BBC he thought the driver was probably from the security service.
Mr Gao told the BBC Chinese Service that he was driving home on Tuesday night when the incident happened.
When he got out of his car to look at the number plate of the offending vehicle, the car tried to hit him, he said.
"The car suddenly started and accelerated towards me. I tried to avoid it, but my hand was hit by the passing car, and I jumped into a roadside garden," he told the BBC.
He said the incident could either have just been aimed at intimidating him, or a deliberate attempt on his life.
Mr Gao's clients have included members of the banned spiritual organisation Falun Gong, members of an underground church, and those who complain they have lost land to the authorities.
In November, the Beijing Bureau of Justice ordered Mr Gao's Beijing legal firm to close for a year on the grounds that it failed to inform authorities of an address change.