London (CNN)Britain’s terror threat level has been reduced to “severe” from “critical,” UK Prime Minister Theresa May said Saturday after meeting with security chiefs.


“The public should be clear about what this means. A threat level of ‘severe’ means an attack is highly likely — the country should remain vigilant,” May said.

The decision to lower the threat rating from its highest level was made by the country’s Joint Terrorism Analysis Centre in light of the arrests made in the Manchester attack investigation, May said. The level had been raised to “critical” after Monday’s deadly bombing.

Investigators are continuing efforts to try to contain the network they believe is behind the suicide attack by Salman Abedi, 22, a British national of Libyan descent who targeted crowds at an Ariana Grande show.

Investigators have identified the location where they believe the Manchester Arena explosive device was assembled, according to a statement from Greater Manchester Police late Saturday.

Police also released two still images of Abedi, taken from CCTV, on Monday evening, the night of the attack. [/restrict]