The family of desperately ill Charlie Gard have posted a defiant tweet to their supporters as doctors consider new evidence saying: 'The fight is not over.'

It comes after hundreds of wellwishers urged Donald Trump to visit the boy in hospital following his tweet earlier this week backing the youngster's family.

The US President risked a diplomatic row by declaring America's support for saving Charlie Gard racking up thousands of retweets and likes within minutes of being posted.

Pope Francis also called for the parents of the baby to be allowed to 'accompany and treat their child until the end'.

Chris Gard and Connie Yates released this new picture of their son Charlie and are 'overwhelmed' after Donald Trump and the Pope offered their support

Connie Yates and Chris Gard are also expected to join supporters in delivering a petition with more than 350,000 signatures to Great Ormond Street Hospital (GOSH) on Sunday.

The family were joined by an American pastor who travelled to the UK to pray at Charlie's bedside and tweets from the campaign account suggested he had initially not been allowed on the neonatal intensive care unit, which also cares for other seriously ill infants.

But Patrick Mahoney, a pastor at the Church on the Hill in Washington DC, later said he had been able to pray 'for a miracle' alongside the parents.

Now members of the so-called Charlie's Army have said they will protest to encourage Mr Trump to go to Great Ormond Street Hospital after he revealed today that that he plans to visit the UK soon.

Ana Belen Suarez Queiro wrote on Facebook: 'He should go... absolutetly! And give him the citizenship and flight to the States and end this agony for this family!'

Chris Gard and Connie Yates are spending the last days of their ten-month-old son Charlie's life with him at hospital in London

Another, named Dan Drouin, said: 'I'm hoping he will visit them and help somehow.'

Others called for protesters to wave banners and signs at Heathrow Airport in a bid to catch the President's attention.

Earlier this week he joined the Pope in vowing to help the desperately ill baby boy as British doctors prepare to withdraw his life-support.

The Vatican said the Pope 'is following with affection and sadness the case of little Charlie Gard and expresses his closeness to his parents'.

They added: 'For this he prays that their wish to accompany and treat their child until the end is not neglected'.

Mr Gard and Miss Yates are spending the last days of their son's life with him, after being given more time before treatment is withdrawn.

If Charlie is unable to be flown across the Atlantic, US medics have said are willing to ship the vital medicine he needs to Great Ormond Street and 'advise their medical staff on administering it if they are willing to do so.'

The US President previously tweeted: 'If we can help little Charlie Gard, as per our friends in the UK and the Pope, we would be delighted to do so'

Connie and Chris paid a visit to the chapel at Great Ormond Street Hospital as they continue to hope they can take him to America for treatment

The 11-month-old has twice survived plans to end his life support – last Friday and again this Monday

On Friday, the little boy won a third dramatic reprieve as doctors bowed to global pressure and gave him another chance.

After being handed fresh evidence, the hospital asked the High Court to reopen the agonising case.

The 11-month-old has twice survived plans to end his life support – last Friday and again this Monday.

Charlie's parents Connie Yates and Chris Gard said the new evidence gave him a much higher chance of survival than previously thought.

Clinicians from the Bambino Gesu paediatric hospital's neurosciences department said tests in mice and patients with a similar, but not the same, genetic condition as Charlie had shown 'dramatic clinical improvements'.

Charlie inherited the faulty RRM2B gene from his parents, affecting the cells responsible for energy production and respiration and leaving him unable to move or breathe without a ventilator. The therapy is not a cure.

Under a High Court ruling, GOSH is forbidden from allowing Charlie to be transferred for nucleoside therapy anywhere.

GOSH also points out that the ruling calls for Charlie's artificial ventilation to be withdrawn and he should receive palliative care only.

GOSH said it will now be for the High Court to make its judgment on the facts and it is acting in Charlie's best interests.

They describe his condition as exceptionally rare, with catastrophic and irreversible brain damage.

Previous legal attempts by Charlie's parents failed as judges in the High Court, Court of Appeal and Supreme Court in London ruled in favour of GOSH doctors, while the European Court of Human Rights declined to hear the couple's appeal.

Charlie's case will be heard by Mr Justice Francis on Monday at 2pm, according to a High Court listing.