YEREVAN, MAY 24, ARMENPRESS. The UK terror threat level has been raised to its highest level of "critical", meaning further attacks may be imminent, Theresa May has said, BBC reported.

Military personnel will now be deployed to protect key sites under the new threat level.

The change in terror threat comes after investigators were unable to rule out whether suspect Salman Abedi acted alone, the prime minister said.

The prime minister said soldiers would be placed in key public locations to support armed police in protecting the public.

Military personnel may also be seen at other events over the coming weeks, such as concerts, Mrs May said, working under the command of police officers.

The prime minister said she did not want the public to feel "unduly alarmed" but said it was a "proportionate and sensible response".

The highest threat level, which is decided by the Joint Terrorism Analysis Centre - a group of experts from the police, government departments and agencies - has only been reached twice before.

22 people died when a suicide bomber detonated and IED in Manchester Arena, England, during a concert of US pop star Ariana Grande. More than 50 people have been injured.