A British member of Parliament has died after being shot outside a meeting with constituents in northern England on Thursday.

Jo Cox, 41, who was with the opposition Labour Party, was shot at about 1 p.m. local time as she prepared to hold a meeting for constituents in Birstall near Leeds, according to police. She was pronounced dead shortly before 2 p.m.

"We are not in a position to discuss any motive at this time, and we are not looking for anyone else in connection with this incident at present," acting Chief Const. Dee Collins of West Yorkshire Police said during a brief news conference.

In a news conference police said they have one under arrest and are searching for no one else 4:14

Witnesses described a man shooting Cox several times and appearing also to stab her as she lay on the pavement. Police said they have a suspect in custody — a 52-year-old man — and are not looking for anyone else.

"This is a truly shocking incident," said Mark Burns-Williamson, police and crime commissioner for West Yorkshire.

"I've worked closely with Jo since she was elected and I'm deeply shocked that a talented young woman has been so senselessly attacked and killed whilst working in her constituency and serving her community."

A 77-year-old man was also injured in the altercation, but police said he is expected to survive.

Bleeding on the ground

Details of the shooting are still unclear, and it is not known if Cox was the gunman's target or if the attack was politically motivated.

One eyewitness told the Press Association that Cox had intervened in a scuffle between two men. One of them had pulled a gun from a bag and it was fired twice.

"She fell between two cars and I came and saw her bleeding on the floor," said Hithem Ben Abdallah.

Emergency services arrived and tended to Cox after about 15 minutes, he said.

Café owner Clarke Rothwell witnessed the attack on Cox and described the scene to the BBC.

Police stand behind a cordon in Birstall, U.K. following an fatal attack on local MP Jo Cox, who was with the opposition Labour Party. (Craig Brough/Reuters)

"I looked round, there's a man stood there in his 50s with a white baseball cap on and a jacket with a gun — an old-fashioned looking gun in his hand — and he shot this lady once and then he shot her again," Rothwell said.

Cox fell to the ground, and the gunman leaned over and "shot her once more in the face area," Rothwell said.

The BBC reported a witness said the shooter had shouted out "Britain first" at least twice, which is the name of a right-wing group that describes itself on its website as "a patriotic political party and street defence organization."

Jayda Fransen, deputy leader of Britain First, said the shooting was "absolutely disgusting" and suggested the phrase was a common slogan being used in the EU referendum campaign by those who support Brexit.

At least one other media report said a witness quoted did not hear "Britain first" shouted. It is unclear if the witness is same person cited by BBC.

"We were as shocked to hear these reports as everyone else," Fransen told Reuters. "At the moment would point out this is hearsay, we are keen to verify the comments but we can only do that when the police provide more details."

Police told the Guardian they are investigating those reports.

Scene in Birstall where eye witness quoted says did NOT hear anyone shouting "Britain First" <a href="https://twitter.com/hashtag/JoCox?src=hash">#JoCox</a> <a href="https://t.co/hkadF3W4QK">pic.twitter.com/hkadF3W4QK</a> —@andybell5news

Zest for life

Cox's husband Brendan released a statement about his wife's death Thursday evening, saying she would have "no regrets" about how she lived her life.

"Today is the beginning of a new chapter in our lives. More difficult, more painful, less joyful, less full of love. I and Jo's friends and family are going to work every moment of our lives to love and nurture our kids and to fight against the hate that killed Jo," the statement said.

"Jo believed in a better world and she fought for it every day of her life with an energy, and a zest for life that would exhaust most people.

"She would have wanted two things above all else to happen now, one that our precious children are bathed in love and two, that we all unite to fight against the hatred that killed her. Hate doesn't have a creed, race or religion, it is poisonous."

Campaigns suspended

Northern-born Cox was a Cambridge University graduate and aid worker before becoming Labour lawmaker for the constituency of Batley and Spen in 2015. Known for her work on women's issues, Cox has worked with several charities.

She made finding a solution to the Syrian civil war a top priority and was critical of Britain's reluctance to deepen its military involvement against the extremist group Islamic State in Iraq and Syria as part of that effort.

In recent weeks, she campaigned for Britain to remain in the 28-member European Union ahead of the country's June 23 referendum, and last week published an op-ed in the Yorkshire Post, in which she said leaving the EU is no answer to the "real concerns" surrounding the country's immigration policy.

British lawmakers are currently not in Parliament ahead of next week's referendum.

Groups on both sides of the referendum have suspended their campaigns following the attack.

Prime Minister David Cameron said "this is absolutely tragic and dreadful news."

"We have lost a great star," he said." She was a great campaigning MP with huge compassion and a big heart."

The death of Jo Cox is a tragedy. She was a committed and caring MP. My thoughts are with her husband Brendan and her two young children. —@David_Cameron

Shocked to hear terrible news about brilliant MP and friend Jo Cox. Thinking of her and praying for her and family. —@SadiqKhan

Labour leader Jeremy Corbyn said "the whole of the Labour Party and Labour family — and indeed the whole country — will be in shock at the horrific murder of Jo Cox today."

No serving U.K. member of Parliament has been killed since 1990, when the Irish Republican Army killed Conservative lawmaker Ian Gow with a booby-trap bomb placed under his car outside his English home. A former lawmaker, Donald Kaberry, was injured in an IRA bombing in 1990 and died the next year.

British security officials said Cox's shooting didn't appear to be related to international terrorism. Domestic terrorism, however, has not been ruled out.

Both the Vote Leave and Britain Stronger in Europe campaigns have been suspended.

The rival sides in the referendum have been canvassing feverishly ahead of what is expected to be a close vote.

International reaction

Cox's death also brought international reaction, including a moment of silence in Ottawa during question period in the House of Commons following an emotional tribute from NDP MP Nathan Cullen.

Gabrielle Giffords, the former member of the U.S. House of Representatives who survived being shot in the head in 2011, tweeted her condolences.

"Absolutely sickened to hear of the assassination of Jo Cox. She was young, courageous, and hardworking. A rising star, mother, and wife."