UK terror threat lowered days after London Tube bomb

The UK's terror threat level has been lowered from 'critical' to 'severe', Home Secretary Amber Rudd has announced.

It means an attack is considered highly likely rather than imminent.

The level had been raised on Friday to the highest - critical - following the bucket bomb blast at Parsons Green Tube station that left 30 passengers injured.

Troops were deployed to key locations so armed police were freed up to patrol the streets.

Two people have been arrested in connection with the west London bombing.

Announcing the threat level was being lowered, Rudd said: "I would urge everybody to continue to be vigilant but not alarmed.

"During the next few days, the military will return to their original positions.

"I'd like to take this opportunity to thank them for their hard work, and also the police, the security services and the emergency services who did such a fantastic job."

Officers in sight

Rudd added that the Joint Terrorism Analysis Centre, which sets the threat level, had decided "sufficient progress has been made" to lower it.

But she warned the Parsons Green investigation was "still an ongoing operation".

Assistant Commissioner Mark Rowley, the UK's most senior counter-terrorism officer, also announced that police were "getting a greater understanding of the preparation of the device".

[caption id="attachment_5657" align="aligncenter" width="500"] The source of the explosion. ©Twitter/andyjohnw[/caption]

He confirmed more officers - some armed - would remain in place on the streets and transport networks at the beginning of the week.

The announcements come after two men were arrested in connection with the Tube blast.

An 18-year-old man was arrested in the departure lounge of Dover port, in Kent, and a 21-year-old man was detained in Hounslow, west London.