ARMED officers from the "Civil Nuclear Constabulary" are in Merseyside supporting police after the Manchester bombing.

The move came as the Prime Minister initiated Operation Temperer – the mobilisation plan for military support to the police service following a major terrorist attack.

Officers from the CNC - the UK's specialist armed police service - will be patrolling nominated sites to provide extra security. 

They are scheduled to be in the area for the next seven days and will operate under command and control of Merseyside Police.

A police spokesman said: "As a precautionary measure we have increased the number of officers on duty to provide a highly visible, reassurance presence - both overtly armed and unarmed - across the country for as long as is needed.

"We urge the public to remain alert but not alarmed - the police service and our partners are doing everything we can to help protect the security of our communities, public institutions, critical national infrastructure, and businesses and places of interest.

"Our security measures and activities are under constant review to reflect where the threats exist and the level of threat we are facing.

"Be vigilant. If you suspect it, report it.

"Nobody is better placed to detect something that is out of place in their communities than the people living in them.

"If you get caught up in the rare event of a weapons attack we urge you to follow the Run, Hide, Tell advice."

This morning counter-terror police investigating the Arena bombing carried out fresh raids searching addresses in Manchester and Merseyside.

One man was arrested in the Moss Side area of Manchester in the early hours, and detectives searched a property in St Helens.

Eight men are in custody in connection with Monday’s atrocity, with police and security agencies working at pace amid fears of further attacks.

If you see any suspicious activity call the Anti-Terrorist Hotline on 0800 789 321 - in an emergency always dial 999.