"The U.S. Embassy has received information of possible threats against Westerners in the Sanlitun area of Beijing, on or around Christmas Day," according to an alert posted on the U.S. Embassy website and emailed to American citizens in Beijing.
By Thursday afternoon, the Beijing police also issued a medium-level security alert for the Chinese capital and heavily-armed police began patrols across the city. The Sanlitun neighborhood is home to number of foreign embassies as well as a large open-air shopping center. At night, it becomes a popular nightlife district for locals and foreigners alike.
The British Embassy also issued a similar warning to its citizens in the Chinese capital.
The embassies gave no further details on the nature or origins of the potential threats. It is also unclear whether the Beijing security alert was related to the threats mentioned by the U.S. embassy.
Chinese authorities remain anxious about crowd control after last year's deadly New Year's stampede in Shanghai that killed 36 people.
Sanlitun has seen violence against Westerners recently, with an incident in August where a sword-wielding man attacked a French man and a Chinese woman. The woman later died in the hospital.