A member of the British parliament has been injured after being shot in northern England, UK police and media reports have said, prompting the supension of campainging for next week's EU referendum.

Local media reported on Thursday that Labour party member Jo Cox, 41, had been shot at her advice surgery in Birstall, near the city of Leeds.

Al Jazeera's Barnaby Phillips, reporting from London, said Cox was believed to be in critical condition.

"She was taken by air ambulance from Birstall library near the city of Leeds. Witnesses say she was shot and stabbed and taken by air ambulance to Leeds General Infirmary," he said.

A mother of two, Cox has been an MP since 2015 and chairs the all-party parliamentary committee on Syria, Phillips added.

West Yorkshire Police said a 52-year-old man had been arrested by armed police and that a woman in her 40s had suffered serious injuries.

"Very concerned about reports Jo Cox has been injured," Prime Minister David Cameron said on Twitter. "Our thoughts and prayers are with Jo and her family."

A man in his late 40s to early 50s also suffered slight injuries, police said.

One witness told the Press Association that Cox had intervened in a scuffle between two men, one of whom pulled a gun from a bag and then fired twice.

TV footage showed the surrounding area had been sealed off.

EU referendum campaigning suspended

Following the attack, both sides in Britain's upcoming referendum on leaving or staying within the European Union said they were suspending campaigning for the day, while Cameron said he would pull out of a planned rally in Gibraltar.

The Stronger in Europe camp said it was "suspending all campaigning for the day", while a spokesman for the rival Vote Leave group, which is backing a so-called Brexit, said that their "battle bus" had stopped campaigning for the day.

Labour MP Kate Osamor welcomed the decision to suspend campaigning, adding that the attack had caused concern among other politicians over their own security.

"I don't know what the motivation can be, which is more worry for all of us, parliamentarians doing our job," she told Al Jazeera. 

Cox, a Cambridge University graduate and aid worker, became a Labour MP for Batley and Spen last year. Known for her work on women's issues, Cox has worked with several charities.

Source: Al Jazeera and agencies