According to UK's Telegraph, around 50 Chinese mob attacked Gary Locke's car right at the entrance to the US Embassy in Beijing. The car was damaged, but Locke was able to escape after Chinese guards intervened.
The attack took place under the backdrop of China's dispute with Japan over Diaoyu Islands. A State Department spokeswoman reaffirmed US's position that the islands were covered under Article V of the security treaty between US and Japan, a stance seen by China as bias. A few days earlier, the US Defense Secretary Panetta visited Japan on an unscheduled stop on his Asia trip, and announced deployment of one more anti-missile system. Although Panetta stressed that the system was targeting North Korea, the timing clearly was very sensitive in the height of the Sino-Japanese dispute. Panetta also is extending his China stop from 2 days to 4 days.
While evidences had surfaced that violent protests against Japan and Japanese interests in dozens of cities across China were led by official securities forces disguised as mobs, rumor has it that the attack on Locke was a job done by the same group of people. It's revealing to notice that anti-Japanese protests, which had caused damages of billions of dollars in dozens of cities, 'evaporated' all in a sudden without major police crack-down. And then it came the attack to US Ambassador.