A 25-year-old man has been charged with murder and the preparation of terrorist acts after the fatal stabbing of MP Sir David Amess.
Ali Harbi Ali was arrested following the attack at a constituency surgery in Leigh-on-Sea, Essex, on Friday.
Sir David, a Conservative MP since 1983, suffered multiple stab wounds and died at the scene.
Mr Ali is a British man whose father is a former adviser to Somalia's prime minister.
Nick Price, from the Crown Prosecution Service, said: "We will submit to the court that this murder has a terrorist connection, namely that it had both religious and ideological motivations."
Mr Ali is accused of visiting the home of one MP, the Houses of Parliament and the constituency surgery of another MP at various times this year as part of reconnaissance for a potential attack.
On Thursday, Mr Ali, from north London, appeared at Westminster Magistrates' Court. Wearing a grey tracksuit and black-rimmed glasses, he spoke only to confirm his name, age and address.
He was remanded in custody and is due to appear at the Old Bailey on Friday.
Metropolitan Police Assistant Commissioner Matt Jukes sent his "deepest condolences" to the family, friends and colleagues of the MP.
"Sir David's dedication to his family, his constituents and his community, and his positive impact on the lives of so many has been abundantly clear since his death," he said.
Since the killing, a large team of detectives in the Metropolitan Police's Counter Terrorism Command had been "working around the clock" to search several addresses in north London, analyse digital devices and review CCTV, Mr Jukes said.
There have been no other arrests and police are not seeking anyone else, he added.
The Metropolitan Police has been working with Parliament's security team and the Home Office to review the protection of MPs.
Police forces across the country have also been working with individual MPs about their security in their constituencies.
Prime Minister Boris Johnson said: "I hope that the family of David Amess and all those who love him will get the justice they deserve as fast as possible."
He praised the police outreach to MPs on security, but said MPs must not be "intimidated by this appalling murder into changing the way we conduct our Parliamentary business or the way we work in our constituencies - which I think is the last thing David Amess himself would have wanted".
On Tuesday, MPs paid emotional tributes to their colleague, with Mr Johnson saying the killing was a "tragic and senseless death" of one of the "most gentle individuals" to serve in Parliament.
Labour leader Sir Keir Starmer praised him as a "dedicated constituency MP" and fellow Essex MP Mark Francois called him "the best bloke I ever knew".