European countries pledged to raise security measures following Monday's
London's Metropolitan Police said in a statement Tuesday that "detailed plans for protecting public events" over the holiday season were in place. The statement added that the current threat level was already "severe," meaning that an attack was "highly likely."
The U.K. capital's police force said that "the use of large vehicles" in such an event – following the style of Monday's attack on a Berlin Christmas market in which a lorry was driven into a crowd of people – had been taken into consideration. This is not the first time an incident of this kind has taken place in Europe. In July, a truck was driven into a crowd celebrating the Bastille Day holiday in Nice, France.
Other British cities have also implemented precautionary measures. The Greater Manchester Police force released a statement in which Assistant Chief Constable Debbie Ford said that the organization had "strengthened our policing presence at the Manchester Christmas markets and stepped up visible patrols."
Elsewhere in Europe, a spokesperson for the Danish National Police told CNBC via e-mail that, following the incident in Berlin, it had asked police districts to "assess and possibly carry out confidence and safety building measures." The organization added in the statement Tuesday that since early 2015, efforts had been made to "intensify … vigilance."
On Monday, Reuters reported a statement from the French interior ministry that, "security at Christmas markets will be reinforced with immediate effect." It detailed that "security forces will keep to a maximum level of vigilance."