British Prime Minister David Cameron and opposition leader Jeremy Corbyn have jointly paid tribute to the slain Labour MP Jo Cox, and have called for greater tolerance in public debate.

Cameron and Corbyn laid bouquets on Friday in the northern village of Birstall, where Cox, a 41-year-old mother of two, was shot dead a day earlier.

"Where we see hatred, where we find division, where we see intolerance, we must drive it out of our politics and out of our public life and out of our communities," Cameron said.

With only a week until a referendum on whether Britain should leave the EU, which has split the country in two and sparked fiery debate on both sides, Cameron said it was time to "stand back".

Killing of MP Jo Cox halts Brexit campaigning in UK

Many commentators have questioned whether the killing could be linked to the referendum, which has stoked tensions by touching on issues of national identity and immigration.

"She was taken from us in an act of hatred, in a vile act that has killed her. It's an attack on democracy what happened yesterday. It's the well of hatred that killed her," Corbyn, the leader of the main opposition Labour Party, said.

Both sides have halted campaigning as a mark of respect with only a week to go until the knife-edge vote on June 23.

 Jo Cox was known for campaigns for Syrian refugees [Stefan Wermuth/Reuters]

Cox, a former aid worker and pro-EU campaigner, was an advocate for Syrian refugees.

Police arrested a 52-year-old man, named by media as local Thomas Mair, in connection with the murder.

US advocacy group, the Southern Poverty Law Center, said that Mair, who had lived in Birstall for decades, was a "dedicated supporter" of National Alliance, once the primary neo-Nazi organisation in the United States.

The advocacy group said he had spent over $620 on reading material from the National Alliance, which advocated the creation of an all-white homeland and the eradication of Jewish people.

The group also said Mair had purchased a handbook with instructions on how to make a gun, noting that witnesses told British media the attacker used a gun which appeared "old-fashioned" or "home-made".

However, Al Jazeera's Barnaby Phillips, reporting from Birstall, said his neighbours told him Mair was a soft-mannered man who expressed no interest in politics.

"If there were any dark corners, they were extremely well-hidden," Phillips said. "He enjoyed his voluntary work teaching English to foreigners who settled in this area."

Inside Story - Has politics in the UK become too divisive and toxic?

Source: Al Jazeera and agencies