UK raises terrorism threat alert to 'severe'

On Monday night, the UK government elevated the estimated terrorism threat level in the country from "substantial" to "severe," meaning the likelihood of an attack or attempted attack is high.

A "severe" threat level means that there is a belief that an incident is likely, but that no specific information is available as of yet. The next level of threat is "critical," which would mean that there is intelligence on a specific and imminent threat.

The move appears to be in response to Monday night's shooting incident in the city of Vienna, Austria, in which a terrorist stormed into a church and started shooting, leaving four people dead.

"This is a precautionary measure following the horrific events of the last week in France and last night in Austria and is not based on a specific threat. As I've said before, we face a real and serious threat in the UK from terrorism. I would ask the public to remain vigilant and to report any suspicious activity to the police," said British Home Secretary Priti Patel in an interview.

The incidents in France referred to by Patel are the recent knife attack in Nice that killed three innocent people, the shooting of an Orthodox priest, and the beheading of a teacher in Paris after showing depictions of the Prophet Muhammad to his students.