The British parents who took their critically ill child for treatment abroad without doctors' consent were released from custody in Spain on Tuesday after the charges against them were dropped, their lawyer said.
The National Court in Madrid said in a statement that a judge ordered the couple's immediate release after receiving official notification from Britain that authorities there were no longer seeking their extradition.
Reporters outside the Soto del Real prison, about 40 kilometres outside Madrid did not see Brett and Naghemeh King leave, but their lawyer Juan Isidro Fernandez told the Associated Press they had been let go from the prison, which has more than one exit. He said they would attend a news conference in southern Spain on Wednesday to speak about the case.
Their five-year-old son Ashya, who has a severe brain tumour, is in a hospital in Malaga, 500 kilometres from Madrid.
The parents were pursued by police after they took Ashya out of a hospital in southern England against doctors' advice and travelled to Spain, where they planned to sell a property to pay for proton beam radiation therapy in the Czech Republic or the United States.
They were arrested on a British warrant on suspicion of cruelty to a person under 16 years of age. The parents were sent to the prison on Monday after a judge ruled they should be held while a Madrid court considered Britain's extradition request, which was later revoked.
"No further action will be taken against Mr. and Mrs. King," British prosecutors said in a statement earlier Tuesday, adding they were doing it so the family can be reunited as soon as possible.
The case has riveted Britain, with heated debate as to whether authorities acted appropriately in chasing the parents through Europe after they left Southampton General Hospital last week without the consent of doctors.
Prime Minister David Cameron took the highly unusual step of wading personally into the debate, tweeting that he welcomed the prosecution against Ashya's parents being dropped.
"It's important this little boy gets treatment & the love of his family," he wrote.
Police said the arrest warrant was applied for so that Ashya could be found as soon as possible, but the situation is now "not right."
"Our intent was to secure his safety, not to deny him family support at this particularly challenging time in his life," Hampshire Police Chief Constable Andy Marsh said.
Earlier in the day, Cameron told the radio station LBC that the plight of Ashya reminded him of his late son Ivan, who had cerebral palsy and epilepsy. The Prime Minister recalled having his own son sit on his lap and feeding him through a tube.
Jorge Sainz contributed from Madrid and Danica Kirka contributed from London.