Britain raises terror threat level over Iraq, Syria fears

British Home Secretary Theresa May said Friday the country's terror threat risk level was being raised to "severe" due to fears over the situation in Iraq and Syria.

"The increase in the threat level is related to developments in Syria and Iraq where terrorist groups are planning attacks against the West," May said.

"Some of those plots are likely to involve foreign fighters who have traveled there from the UK and Europe to take part in those conflicts."

The US quickly responded to the UK's announcement of the increased threat level, saying there are no plans to raise the US terror alert level.

The "severe" threat level means that a terrorist attack is "highly likely", although May added there was no intelligence to suggest that an attack was imminent. 

She also said that "we face a real and serious threat in the UK from international terrorism. I would urge the public to remain vigilant and to report any suspicious activity to the police."

She said the decision to raise the threat level was made by the Joint Terrorism Analysis Centre (JTAC) and that their judgment about the threat level is "based on the latest intelligence and they are independent of ministers."

Prime Minister David Cameron also addressed the issue in a speech on Friday saying, “What we are facing in Iraq now with ISIL [Islamic State] is a greater and deeper threat to our security than we have known before.”

He went on to say that "with ISIL we are facing a terrorist organisation not being hosted in a country but actually seeking to establish and then violently expand its own terrorist state."

Cameron reaffirmed that at least 500 Britons are believed to have gone to fight in Syria and possibly Iraq. 

The threat level is now at the second highest level out of five possible categories and is at its highest since July 2011.