Boris Johnson has issued a stinging criticism of Jeremy Corbyn's security record by accusing him of siding with "our enemies" as world leaders arrive in the UK for a two-day Nato summit.

The Conservative Party leader has blasted his election rival for his approach to Nato, which is marking its 70th anniversary, and to the threat of Russia.

In an interview with The Sun, the Tory leader said the UK's closest allies were "very anxious" about Mr Corbyn being elected to Number 10 and accused him of being "naive" to the terror risk Britain faces.

READ MORE: Jeremy Corbyn set to tell Donald Trump: 'NHS not for sale'

The Prime Minister even suggested the likes of the US, Canada, Australia and New Zealand - the nations that, with Britain, make up the so-called Five Eyes intelligence-sharing agreement - could stop working closely with the UK if Mr Corbyn became prime minister.

"Every time he has the chance, he sides with our enemies," Mr Johnson told the right-wing newspaper.

"A lot of our allies, particularly the Five Eyes, are very anxious about any future collaboration.

"It is absolutely not a Tory scare story. They have said precisely this."

A Labour spokesman hit back at the remarks, accusing the Tories of trying to "keep people safe on the cheap".

"Jeremy Corbyn has consistently made the right calls in the interests of peace and security at home and abroad and will do whatever is necessary and effective to keep the British people safe," the party spokesman said.

"Real security doesn't just come from strong laws and intelligence, it also comes from effective public services that have the funding they need. You can't keep people safe on the cheap."

Mr Johnson's incendiary remarks were published only hours after Donald Trump's Air Force One touched down at Stanstead Airport, with the US president in Britain for the two-day Nato summit.

Mr Johnson continued to focus his General Election message on pushing for tougher punishments for terrorists, with the pledge of locking them up for longer, despite criticism from the families of the victims of the London Bridge terror attack.

A murderous rampage by Usman Khan on Friday killed two people - Saskia Jones, 23, and Jack Merritt, 25 - in Fishermongers' Hall at a rehabilitation event, before the terror convict was attacked by civilians and shot dead by armed police.

Mr Johnson told supporters at a Tory rally in Colchester on Monday evening that, if put back in Downing Street, he would be "stopping the early release, the automatic early release of serious and violent offenders and terrorists".

But Dave Merritt, father to murdered Jack, said his son would have been "livid" at the political reaction to his death.

"He would be seething at his death, and his life, being used to perpetuate an agenda of hate that he gave his everything fighting against," he told the Guardian.

Labour looked to put visiting Mr Trump and a possible post-Brexit trade deal in the spotlight during the US leader's visit.

Mr Corbyn published his letter to Mr Trump in which he asked for "reassurances" that US negotiators would not look to push up UK medicine prices by seeking access to the NHS for major American pharmaceutical companies.

Mr Corbyn told journalists at a rally in Hastings, East Sussex, that, under a Labour administration, there would "be no deal" if the US pushed for such access into the NHS.

"I am making it very clear we are not allowing our public services to be taken over by anyone outside," he said on Monday.

It comes as questions arose over whether Russian disinformation was behind Labour's 451-page unredacted report that revealed the details of talks between UK and US officials regarding a future trade deal between the two countries.

At a press conference last week, Labour said the document proved there was a Tory plot to sell off the NHS.

Graphika, a social media analytics firm, said it had worked with the Atlantic Council, a US-based international affairs think tank, to uncover what it said were similarities with the leak compared with a major Russian misinformation campaign called Secondary Infektion.

The document had first been made available on online discussion site Reddit in October.

Former Tory leader Iain Duncan Smith told the Daily Telegraph: "If they are using disinformation to fabricate their NHS scare stories, which are anyway not true, that speaks volumes about them."

But a Labour spokesman said it was no surprise senior Tories were looking to discredit the explosive reports.

"Neither the UK nor the US government have denied their authenticity," the party spokesman told the Telegraph.

"Given what they reveal, it's not surprising that there are attempts to muddy the waters to cover up what has been exposed."