The British counter-intelligence service "MI5" has raised the level of terrorist threat in Northern Ireland from "significant" to "severe".

According to the report of APA's British bureau referring to "Sky News", official bodies said that this means that there is a high probability of terrorism.

Northern Ireland Secretary of State Chris Heaton-Harris told the House of Commons that the decision was made by MI5.

"The public should be vigilant but not alarmed and should continue to report their concerns to the Police Service of Northern Ireland," he said.

It should be noted that the Security Service, known as "MI5", is the domestic counter-intelligence and security agency of the United Kingdom.