A bus burst into flames during today's morning rush hour here, killing three people and heightening security concerns in a city on high alert ahead of August's Olympics, according to authorities and witnesses.
The official New China News Agency said there was an explosion, but witnesses said they did not hear any loud noise. They said they saw smoke rising from the vehicle before it was suddenly enveloped by flames as passengers scurried to get out. Police at the scene said three people were killed and 12 others injured.
The news agency said about 50 passengers were on Bus No. 842 in Shanghai's northeast district. One witness, Zhou Rixin, said he saw the fire ripping through the vehicle's roof.
By late morning, more than 20 uniformed and plainclothes government security agents were at the scene, a busy street in a residential area. There was widespread speculation among witnesses and residents nearby that someone may have deliberately started the fire, but no official report of the cause.
Shanghai, though not hosting any major Olympics competition, has been tightening security, as have other cities. Some public events have been canceled or postponed.
On April 25, the U.S. government issued a travel alert for American citizens in China, saying there was heightened risk of extremist groups conducting terrorist acts.