福克斯新闻 英国提高恐怖主义威胁等级（在线收听）

Police here saying they're stepping up patrols after the UK's threat level was raised to "severe". That's the second-highest point on a five-point scale.

Officials saying there's no evidence of an imminent attack. But British Prime Minister David Cameron says terror group Islamic State does pose a grave danger.

(Prime Minister Cameron) "We are facing a terrorist organisation not being hosted in a country, but actually seeking to establish its own terrorist state."

It's the first time the threat level here has been raised since 2010.

In London, Simon Owen, FOX News Radio.