MPs have been told to contact police to review their security following the killing of Jo Cox.
Sky News understands Tory chief whip Mark Harper and Labour counterpart Rosie Winterton issued the advice after Mrs Cox, 41, was shot, stabbed and kicked in the street following a constituency surgery in Birstall, West Yorkshire.
A newspaper report suggests police had been reviewing the mother-of-two’s security after she received threatening messages over a three-month period.
The Times says there is no known link between the reported messages and her killing.
A witness to Thursday’s attack on the Batley and Spen MP said the gunman “walked off very coolly, very slowly”.
A 52-year-old man named locally as Tommy Mair was arrested a mile from the scene.
Conservative MP James Berry told Sky News: “The chief whip has given us very similar advice to the Labour chief whip. The main concern is around public events and surgeries.
“The tragedy here is that Jo was brutally murdered after her constituency surgery, trying to do her democratic duty. That’s a big concern for all MPs who, like me, hold a weekly advice surgery.”
The attack came a week after Tory whip Gavin Barwell was threatened outside his constituency office in Croydon.
And in the hours following Mrs Cox’s death, a man was reportedly detained by police over an abusive phone call made to the office of MP Ben Bradshaw.
Bernard Jenkin, MP for Harwich and North Essex, told Sky News he no longer meets constituents alone.
“There have been times when I have suddenly felt I am in danger,” he said. “I now conduct my surgeries with somebody else present.”
The attack on Mrs Cox was not the first on an MP in their constituency.
Liberal Democrat Nigel Jones, now a peer, was wounded and his aide Andrew Pennington was stabbed to death in a sword attack at the party’s office in Cheltenham in 2000.
In 2010 Labour MP Stephen Timms was stabbed twice in the stomach by a woman who tried to kill him for voting for the Iraq war.
A report for the House of Commons Administration Committee last August revealed that security is a particular concern for women MPs.
Tributes to Mrs Cox have come in from all sides of the political divide and from foreign politicians including US presidential candidate Hillary Clinton.
The MP’s husband Brendan released a statement saying “Jo believed in a better world and she fought for it every day of her life”.
Vigils were held in Westminster and West Yorkshire on Thursday evening.
Meanwhile, the recess in referendum campaigning will continue today out of respect.