The crash killed the driver and two passengers and two tourists, a male and female, China's state-run Xinhua News Agency reported.
The vehicle, a Jeep, struck a guardrail before bursting into flames, police said.
The Los Angeles Times said the accident may have been deliberate, reporting that the vehicle was driven along a sidewalk toward the square's huge portrait of Mao Zedong before it struck the crowd and caught fire.
Tiananmen Square remains a sensitive location and frequently is the scene of attempted protests and self-immolations. It is best-known for the 1989 crackdown on pro-democracy demonstrators.
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