Vatican offers to help terminally ill boy Charlie Gard

International efforts to intervene in the case of Charlie Gard have gathered pace, with the Vatican children's hospital offering to take in the terminally ill boy.

The president of the Bambino Gesu hospital in Rome, Mariella Enoc, told reporters she had asked Great Ormond Street Hospital (GOSH) if the 11-month-old could be transferred.

Her intervention comes after US President Donald Trump and the Pope tweeted their support for the boy, who has been at the centre of a lengthy legal battle between his parents, who wanted him to undergo a US therapy trial, and specialists at the hospital in London, who said the treatment was experimental and would not help.

PICTURED: Chris Gard and Connie Yates with their son Charlie Gard provided by the family, at Great Ormond Street Hospital, in London. Photo: AP

The Vatican's pediatric hospital stepped in after Pope Francis called for Charlie's parents, Chris Gard and Connie Yates, to be allowed to "accompany and treat their child until the end".

"I was contacted by the mother, who is a very determined and decisive person and doesn't want to be stopped by anything," Enoc said.

GOSH responded that Charlie could not be moved for legal reasons, she said.

His parents are spending the last days of their son's life with him after being given more time before his life support is turned off.

The 11-month-old has been at the centre of a long legal battle. Photo: AAP

Charlie suffers from a rare genetic condition leaves him unable to move his arms and legs or to breathe unaided.

He has a form of mitochondrial disease - a genetic condition that causes progressive muscle weakness and brain damage.

Charlie's plight has touched people around the world and the family has received donations totalling more than STG1.3 million ($A2.2 million) to take him to the US for therapy.