Sir David Amess, a Tory MP from Leigh-on-Sea, Essex, died after being stabbed numerous times during a constituency surgery at a church.
The Conservative MP, 69, was said to be getting treatment at the site but was unable to be revived.
The area has been cordoned off by police, and the street outside has been put on lockdown.
Following the incident, Essex Police detained a man.
At around 12 p.m., a man entered into his constituency surgery and stabbed him many times, according to Sky News.
“He was stabbed several times,” John Lamb, a local councilor at the scene, said. Shortly before 3pm a spokesperson for Essex Police said: “A man has been arrested on suspicion of murder after a man was stabbed in #LeighonSea.
“We were called to Eastwood Road North shortly after 12.05 pm. Sadly, a man later died.
“A man was arrested at the scene. We are not looking for anyone else.”
The incident sent shockwaves through the normally peaceful neighborhood.
Witnesses on the site described the commotion that followed Sir David’s assassination. According to Anthony Gavin Fitch, 38, “I was exiting my vehicle to look at a job after parking up outside the church.
“As I was walking across the road I saw a few people sitting on the wall outside the church and one was on the phone to the police.
“She was saying ‘get here as soon as you can, he’s still in the building’. She was wearing a badge with the Tory logo on it.
“He was taken away by two officers with armed police behind him. He didn’t make any noise.
“I heard it was a stabbing from a lady who was inside the church at the time. She was upset and said David Amess had been stabbed three times.
“She said there was an altercation and then the suspect stabbed him. I think he’s still in the church, he (Sir David) hasn’t been taken out.”
In the charming beach resort, an air ambulance has arrived.
The incident, according to one eyewitness, was “very distressing” and described seeing someone being taken out of the building and put into the back of a police car before he was asked to leave the area.
“At that point obviously we knew something serious had happened,” he told LBC.
“Within five minutes we’d been informed by someone who was actually in the building what had happened and apparently he (Sir David Amess) had been stabbed quite a few times. It’s very distressing that’s for sure.”
“It’s just a residential street with a Methodist church on the road and you don’t often hear of things like this going on down this way.
“To have it next door to where you’re working is obviously very upsetting and very unlike what it’s like around here. It’s very odd and it’s very distressing, that’s for sure.”
A woman walked out of the church yelling ‘he’s not breathing,’ according to Lee Jordison, 40, who observed the aftermath of the incident.
“I was working in our shop about 100 meters away when I was alerted to ambulances and police cars going past.
“I took a walk down the road and saw police setting up a cordon. I spoke to someone walking up the road and they said there was a stabbing in the church.
“There were lots of ambulances and police with machine guns.
“I heard from a couple of people that a lady came out screaming phoning the police saying ‘please get here quickly he’s not breathing.”
Julia Arnold, the MP’s wife, was not present at the moment, though she does assist him with casework.
At 2.30 p.m., armed cops were still on the scene.
Sir David is considered to be on the Tory party’s right-wing, having voted against laws promoting LGBT rights such as equal age of consent and same-sex marriage.
He spoke out against anti-social behavior and knife crime earlier this year, and he was a strong supporter of Brexit.
His most recent tweet notified followers of today’s constituency surgery.
Labour leader Keir Starmer tweeted: “Horrific and deeply shocking news. Thinking of David, his family, and his staff.”
His deputy Angela Rayner wrote: “I’m horrified by the reports regarding David Amess and an incident at his constituency surgery today.
“We don’t know the details yet but on behalf of all of us in the Labour Party I want to say all of our thoughts are with David and we all hope that he pulls through and is ok.”
Brendan Cox, the husband of murdered MP Jo, tweeted: “Attacking our elected representatives is an attack on democracy itself.
“There is no excuse, no justification. It is as cowardly as it gets.”
Other MPs also shared their shock at the news.
Senior Tory Sir Iain Duncan Smith said: “My thoughts are with David Amess MP and his family at this awful time. Praying for a full recovery following this appalling, shocking news. This angry, violent behavior cannot be tolerated in politics or any other walk of life.”
Tory MP for Bishop Auckland Dehenna Davison tweeted: “Absolutely horrendous news. David is one of the kindest, most supportive, most dedicated people I know. My thoughts are with him and his family.”
Lib Dem leader Sir Ed Davey said: “Sending my thoughts and prayers to David Amess, his family and friends. Such shocking and terrible news.”
A spokesman for Sir David’s office in Westminster said: “The incident has happened. I don’t know what the incident is. We are still waiting.”
An employee of Jean’s Laundry, which is located near Belfair’s Methodist Church, said she was unaware of the incident but had seen emergency cars pass by.
“We just saw all the police and the ambulances turning up, it was probably about half-past 12 or just before then,” she told the PA news agency.
“I saw about two or three ambulances and then an undercover police car and other police cars going past.
“There’s usually people walking past, elderly people walking to the shops. We’ve still got no idea what’s going on, we’re not very busy on a Friday and no one has come in to talk to us about it.”
Opportunities for media to film the start of a Cabinet meeting on Friday have been canceled, as has a planned interview with Prime Minister Boris Johnson.
It is unclear whether the Cabinet meeting will take place.
Several MPs have been attacked in recent years.
Labour MP Jo Cox, 41, was assassinated a week before the 2016 Brexit referendum in Birstall, West Yorks, in her Batley and Spen district.
Thomas Mair, a far-right terrorist who shouted “Britain first!” before attacking the mother of two, shot and stabbed her.
He was found guilty of murder and sentenced to life in prison.
Roshanara Choudhry, then 21, stabbed Labour MP Stephen Timms during a constituency surgery in 2010.
Choudury told cops she wanted “vengeance for the people of Iraq.”
Mr. Timms had advocated the US-led invasion of Iraq in 2003.
She was convicted of attempted murder and sentenced to life in prison. She was sentenced to a minimum of 15 years in prison by the judge.
Mr. Timms, now 66, survived the attack and is still a member of the East Ham constituency in London.
Andrew Pennington, an aide to Lib Dem MP Nigel Jones, was slain in Cheltenham, Glos, in 2000 while assisting Mr. Jones with a constituency surgery.
Mr. Jones was attacked with a samurai sword by Robert Ashman, whom the MP had been assisting with legal matters.
Mr. Pennington raced to assist, but Ashman turned on him and stabbed him to death. He pleaded manslaughter in the death of Mr. Pennington on the basis of reduced responsibility and was convicted by a jury of attempting to murder the MP.
A judge committed him to a secure hospital for an undetermined amount of time. He was released in 2008.
