Image copyright Leave.EU

The Leave.EU group has been criticised after posting a message on social media linking the fatal shooting in Orlando to its campaign to exit the EU.

It sent a tweet with the words "act now before we see an Orlando-style tragedy here before too long".

The tweet suggested Islamist extremism was a "real threat to our way of life" and urged people to vote leave "for greater security" on 23 June.

The message has been condemned by both Remain and Leave campaigners.

Education Secretary Nicky Morgan said it was "really shameful" while Labour's Hilary Benn said it was "cowardly". Home Secretary Theresa May told MPs it was "utterly irresponsible".

'Inappropriate'

Leading figures in the Vote Leave campaign, which went head-to-head with Leave.EU to win the battle to become the official Out campaign, also disassociated themselves from the message, which appeared on Leave.EU's official Twitter account.

It has since been deleted, although an identical Tweet later appeared on the campaign group's feed.

Labour MP Gisela Stuart said it was "inappropriate" and politicians on either side of the debate had a responsibility to "be very careful how we express ourselves".

Former Cabinet minister Iain Duncan Smith said it was "completely pointless to make something out of a tragedy in America that has nothing to do with this debate".

He told Radio 4's World at One. "I abhor anybody that tries to make capital out of that."

Featuring an image of armed militants from the self-styled Islamic State (IS) group, Leave.EU's tweet suggested the "free movement of Kalashnikovs helps terrorists".

Farage reaction

Leave.EU, which is funded by UKIP donor Arron Banks, has yet to comment on the tweet. Despite failing to become the official Out group, Leave.EU has continued to campaign hard, particularly over the issue of immigration.

UKIP leader Nigel Farage said that although it had "nothing to do" with him, he understood the tweet had been approved by an "office junior".

"I'm not in any way formally associated with the organisation. I just think generally after a horrible tragedy it's best to wait a bit and keep quiet," he said during a campaign visit to Sittingbourne in Kent.

Pressed on Hilary Benn's call for him to apologise, he replied: "I would ask for Hilary Benn to apologise for the crimes of Chairman Mao," adding that "Hilary Benn is as close to Chairman Mao as I am to Leave.EU".

The shooting in the Pulse LGBT nightclub in Orlando, in which 49 people were killed and more than 50 injured, was the single worst mass shooting in recent US history.

The House of Commons has observed a one minute's silence for the victims of what Speaker John Bercow called "a homophobic terrorist slaughter". A vigil will be held later in Soho, in London, to be attended by Labour leader Jeremy Corbyn and Mayor of London Sadiq Khan.

Gunman Omar Mateen, a US citizen of Afghan descent, was killed by the police after they stormed the club and rescued a number of hostages. He was not on a terrorism watch list but had been spoken to by the FBI in the past over "inflammatory" comments.

US authorities say he pledged allegiance to IS shortly before the attack but President Barack Obama said there was no clear evidence that he was directed by the jihaddist group.