LONDON -- The murder of British lawmaker David Amess was declared a terrorist incident by London's metropolitan police on Saturday.

Britain's ruling Conservative Party's member of the parliament (MP) David Amess has died after being stabbed on Friday at a constituency meeting in Essex, a county in southeastern England.

As tributes continued to pour in for the 69-years-old lawmaker, a statement released early Saturday by the metropolitan's counterterrorism unit confirmed the crime as an act of terrorism.

"The early investigation has revealed a potential motivation linked to Islamist extremism," said a statement released by the counterterrorism unit.

The suspect, a 25-years-old male, was arrested at the scene of the crime and questioned by detectives. He is being held in custody at a police station in Essex.

As part of the investigation, police are currently carrying out searches at two addresses in the London area.

It is believed the suspect acted alone, police say.

Meanwhile, flags are flying at half-mast at 10 Downing Street and at the Houses of Parliament where Amess served as MP for Southend West in Essex.

Amess was the second MP in Britain to be murdered within five years. Yorkshire MP Jo Cox was murdered by a far-right extremist in 2016.

The latest killing has reopened a debate about the safety of politicians as they conduct meetings with their constituents.

Many MPs insist on face-to-face meetings with constituents to discuss their problems and issues, known as a surgery, which is one of the hallmarks of political life in Britain.

"In the coming days we will need to discuss and examine MPs' security and any measures to be taken," Speaker of the House of Commons Lindsay Hoyle said in a statement.

He said he was shocked and deeply distressed by the killing. "This is an incident that will send shockwaves across the parliamentary community and the whole country," said Hoyle.

British Home Secretary Priti Patel has told all police forces in Britain to review security arrangements for MPs with immediate effect following the attack.

British Prime Minister Boris Johnson also paid tribute to Amess, describing him as one of the kindest, nicest, most gentle people in politics.

Politicians will return Monday to the House of Commons following a recess, and the slaying of one of their own is expected to dominate proceedings in the chamber.