BEIJING (AFP) - - Three men attempted to set themselves on fire near Tiananmen Square in Beijing on Wednesday in protest over an unspecified grievance, police in the capital said.

The three men sat in a vehicle and started the fire just before 3:00 pm (0700 GMT) at an intersection in a busy shopping area, according to a police statement faxed to AFP.

"The three men had come to Beijing to present a petition over a problem," said the statement from Beijing Public Security Bureau's press office, giving no other details on the motive.

The statement said two of the men were taken to hospital with injuries that were not life threatening. Their car had licence plates from outside Beijing.

However, state-run Xinhua news agency cited an unnamed eyewitness as saying police took away two of the men, while the third left in an ambulance.

Under a system dating from imperial times, Chinese can petition to central government authorities in Beijing over injustices or unresolved disputes.

However, many such petitioners complain of unresponsiveness to their concerns and occasionally lash out in frustration, while others report being jailed by authorities.

The area where the incident occurred is about one kilometre (0.6 miles) from Tiananmen Square, the scene of pro-democracy protests in 1989 that the Chinese military crushed with deadly force.

It occurred on the capital's main east to west street, which passes Tiananmen Square, the national congress building and other top government institutions.

Xinhua carried sparse reports on its English-language service, but there was no mention of the incident on its Chinese wire, or in any other organs of the nation's state-run press.

Traffic flowed normally along Changan Avenue a little over two hours after the incident, according to an AFP reporter at the scene.

Police, hotel security guards, traffic wardens, and staff at businesses in the immediate vicinity told the reporter that they had seen nothing.

There were no indications at the intersection of a recent fire there.

Tiananmen Square and surrounding areas have seen several instances of attempted self-immolation in recent years by people frustrated over perceived injustices experienced under China's ruling Communist Party.

In 2005, a 53-year-old man from eastern China doused himself in gasoline and set himself ablaze on the tourist-packed square, in a protest that authorities said was over unpaid wages.

Another man that year attempted self-immolation at the site of Wednesday's incident in a protest over a property dispute, police said then.

There were at least four self-immolation attempts in 2003 near the square by people angry over grievances ranging from the seizure of their businesses to perceived failure of police to solve crimes committed against them, authorities and human rights groups said.

In each case, guards at the heavily patrolled square thwarted the suicide attempts.

China's state media also reported in 2001 that five adherents of the banned Falungong spiritual sect attempted self-immolation at Tiananmen, with one of them dying. Falungong however said Chinese authorities staged the incident.