China has tightened security following a series of suspected grudge bombings across the country.
Barricades have been installed outside the US embassy complex in central Beijing, with vehicles, bicycles and pedestrians being redirected.
There was speculation that heightened security was related to a bombing of a McDonald's at the weekend and 24 explosions in four cities over the past three days.
The McDonald's bomb in Xian, capital of northern China's Shaanxi province, exploded early on Saturday evening, killing two people and injuring 27 others. One man was killed instantly and another died later.
There has been speculation the blast could be linked to Islamic separatists, but police in Xian have ruled out any connection.
Twenty-two bombs exploded in two cities in Guangdong province, southern China, on Friday, local media said. They were planted by a man seeking revenge against his former in-laws and others, reports said. Five people, including the bomber, died and seven were injured.
On Sunday, a bomb went off outside the home of a local official at a collective farm near Guigang city in southwestern Guangxi province, but no one was hurt, state media said.
Observers have blamed the bombings on a crumbling social structure coupled with easy access to explosives - used widely in construction work - and a popular belief that China's legal system is useless for addressing grievances.
AFP