LONDON — Britain's government has raised the nation's terror threat level from "substantial" to "severe," meaning such an attack is considered highly likely.
A "substantial" threat level means there is a strong possibility of an attack. "Severe" is the second highest level of alert in Britain.
In announcing the change Friday, Home Secretary Alan Johnson said: "This means that a terrorist attack is highly likely, but I should stress that there is no intelligence to suggest than an attack is imminent."
He did not identify any terrorist groups or countries that had raised Britain's suspicions, but earlier this week Britain suspended direct flights to Yemen's capital in response to the growing threat from al-Qaida-affiliated militants based in the country.