A five-year-old boy with a brain tumour who has been taken from a UK hospital by his parents against doctors' advice may be in Spain, British police say.
Ashya King's family took him from Southampton General Hospital on Thursday and travelled on a ferry to France that day.
Police were told by the hospital that the youngster was missing more than six hours after he was taken by his parents, Jehovah's Witnesses Brett King, 51, and Naghemeh King, 45.
Hampshire Constabulary said they had "positive information" to suggest that Ashya's family may now be in Spain where they have "strong links" to the Marbella area.
"The need to find Ashya is now desperate," Assistant Chief Constable Chris Shead said.
"It is really important that we find him and ensure he receives medical attention at the earliest opportunity.
"We still don't know whether the King family have any spare batteries for the machine which administers food, the knowledge, or any way of recharging the battery.
"Without properly administered food Ashya's situation is very serious.
"We still urge everyone to please help us find him."
Police said they are now working closely with Spanish authorities to find Ashya.
The search widened considerably when Interpol sent out a missing persons alert to each of its 190 member countries.
Ashya is in a wheelchair and is fed through a tube. He has undergone "extensive surgery", with his last operation seven days ago.
Police have warned that the battery-operated feeding system "is likely to have expired" and his health will "deteriorate rapidly" without urgent medical care.
"Time is running out for this little boy," Mr Shead said.
"We need to find him and we need to find him urgently."
A family friend claimed Ashya's family had "run away in desperation" because they cannot accept nothing can be done for their son.
"This is my mother's friend, she has run away in desperation because they cannot accept that there is nothing that can be done for their son and want to look for help abroad," Katie Fletcher wrote on Hampshire Constabulary's Facebook page.
"Please don't judge, they are a very sweet loving family and I can only believe they are doing this because they want to help their son."
The Kings boarded a cross-Channel ferry from Portsmouth to Cherbourg with Ashya's six siblings on Thursday.
Ashya is likely to be in a wheelchair or buggy, he cannot communicate verbally and is immobile, police have said.