MI5, the United Kingdom’s domestic counterintelligence and security agency, has raised the terrorism threat level in Northern Ireland from “substantial” to “severe,” meaning an attack is highly likely.

The decision, announced by U.K. Secretary of State for Northern Ireland Chris Heaton-Harris on Tuesday, comes days before a possible visit to the country by President Biden. Biden’s visit would coincide with the anniversary of the Good Friday Agreement, also known as the Belfast Agreement, which brought an end to decades of sectarian violence between Irish republicans and unionists.

Heaton-Harris told CNN that the move was made after an uptick in “activity relating to Northern Ireland-related terrorism.”

In late February, a high profile police officer in the country, Detective Chief Inspector John Caldwell, was shot several times in front of his son and other children at a sports complex in Omagh, County Tyrone.

At the time of the attack, the police service in Northern Ireland said the force was focused on “violent dissident republicans,” and many people have been arrested since the attack, according to CNN.

Biden told reporters earlier this month that he intends to make the trip after meeting with British Prime Minister Rishi Sunak. Sunak was in California at the time to formalize the AUKUS security agreement along with Australian Prime Minister Anthony Albanese.

“It’s great pleasure to be here, and I look forward to our conversations and also importantly, we invite you to Northern Ireland, which hopefully you will be able to do — so we can commemorate the anniversary of the Good Friday Agreement,” he told Biden at the time. “I know it’s something very special and personal to you. We’d love to have you.”

Biden replied, “Twenty-five years. It seems like yesterday. Like yesterday. Thank you.”

It is unclear whether the upgraded terrorism threat level will impact Biden’s plans to visit the country.