Canada and at least four other Western countries took the unusual step of issuing Christmas security warnings for travellers after learning of threats targeting foreigners in a popular Beijing diplomatic and entertainment district

Beijing is generally safe and criminals rarely target travellers, although the fashionable Sanlitun bar and restaurant district occasionally sees fights. In August, a lone attacker fatally stabbed a Chinese woman there and injured a French man in the stabbing as well.

'High degree of caution'

Global Affairs Canada suggests Canadians "exercise a high degree of caution due to the occurrence of isolated acts of violence, including bombings and protests," according to an advisory issued at 6:13 a.m. ET.

Chinese police stepped up patrols in the district on Thursday following the warnings.

Photographs taken by a Reuters photographer showed armed policemen standing guard outside various shops.

Regular police tend not to carry guns in China and gun crime is uncommon. The U.S. Embassy said in a brief statement it had "received information of possible threats" against westerners in Sanlitun, also home to many embassies, on or around Christmas Day.

The French Embassy, Britain's Foreign Office and Australia's Department of Foreign Affairs issued similar warnings.

Chinese Foreign Ministry spokesman Hong Lei said he was aware of the reports and that the government paid great attention to foreigners' safety.

Yellow security alert

Beijing police, in a statement on their official microblog, said they had issued a "yellow" security alert for Christmas and New Year, the second lowest level, focused on areas like malls, which are likely to see more people visiting during the festivities.

"Beijing police are planning ahead and taking many measures ... to ensure good public order," it said.

Christmas is not a holiday in officially atheist China, but more and more young people celebrate it as they view it as a sophisticated Western custom and excuse to give gifts.

Beijing has been on much higher alert overall, with patrols by armed police in popular shopping and tourism sites, since a fatal car crash in 2013 at the top edge of Tiananmen Square in which five people died.

The government blamed that incident on Islamist militants from China's unruly far western region of Xinjiang, where hundreds have died in unrest in recent years.