The fatal stabbing of a British lawmaker on Friday is being declared a terrorist incident and will be investigated as such with a potential link to Islamic extremism, authorities said. 

The probe into the death of David Amess, 69, will be led by the Counter Terrorism Command of the Metropolitan Police, the agency Friday. 

Amess was speaking at a Methodist Church in Essex when a man entered and stabbed him, authorities said. Police arrived after 12:05 p.m. local time and arrested a man for the stabbing.

Amess was stabbed multiple times and died at the scene. The suspect, an unidentified 25-year-old man, is being held in police custody in Essex.

"It is believed that he acted alone, and we are not seeking anyone else in connection with the incident at this time," police said.   

"David was a man who believed passionately in this country and in its future," Johnson said in a video accompanying the tweet. "We've lost today a fine public servant and a much-loved friend and colleague."

The slaying came five years after another member of British Parliament, or MP, Jo Cox, was killed by a man with white supremacist views. Cox, 41, a member of the Labour Party, was shot and stabbed in June 2016 outside a library where she was slated to meet with her constituency.