Athens - Greek authorities have sought help from Interpol to identify a young blonde girl whose discovery in a Roma camp has sparked worldwide concern and interest in other child disappearance cases.
The cross-border police agency said it has sent out the girl's photo and DNA profile to all of its 190 member countries.
"Until now, a comparison of the girl's profile against Interpol's global DNA database has not produced a match," the organisation based in the French city of Lyon said in a statement last Tuesday.
At the same time, investigators are seeking clues in other missing child cases around the globe.
"There are nearly a dozen disappearance cases from countries such as the US, Sweden, Poland and France that are being more closely investigated," Panagiotis Pardalis, a spokesperson for the Smile of the Child charity that has been assigned care of the girl, told AFP.
In Washington, deputy US State Department spokesperson Marie Harf said: "At this time, we have no information to indicate that the child [in Greece] is a US citizen."
The girl, known as Maria and dubbed the 'blonde angel', was found by police last week in a Roma camp near the town of Farsala in central Greece.
Initially thought to be four years old, but later confirmed from dental checks to be five or six, she was kept by a Roma couple who were placed in pre-trial detention on Monday for allegedly abducting her.
The couple, a 39-year-old man and his 40-year-old wife, deny the charge and claim that she was voluntarily handed over by her Bulgarian Roma mother who could not care for her.
The Greek Supreme Court has ordered that birth certificates delivered over the past six years be reviewed.
Prosecutors across the country are expected to look into certificates that could conceal "possible cases of human trafficking, abductions and illegal adoptions", the court said.
Smile of the Child has said Maria is at an unidentified Athens hospital for health tests and will soon be taken to one of the organisation's care homes.
Parents 'living in agony'
The girl's discovery, news of which has spread across social media, has struck a powerful chord with parents of missing children around the world, including those of British girl Madeleine McCann, who vanished in Portugal in May 2007 days before her fourth birthday.
It has also led to a case that has sparked comparisons in Ireland where police have removed a seven-year-old girl with blonde hair and blue eyes from a Roma family living in a Dublin suburb.
Documents that the girls' parents handed over have failed to satisfy police, and DNA tests may now be conducted, the Sunday World newspaper said
And in the United States, a family in Kansas City, whose 11-month-old daughter disappeared from their home in 2011, have contacted Greek authorities - although the girl found in Greece is older than their child would be now.
The Smile of the Child has received more than 8 000 calls from around the world since this weekend, Pardalis said.
"This case has highlighted the problem and the need to deal with it. There are [parents of missing children] who have been living in agony for years. We tend to forget these cases exist," he said.
According to police, the Roma couple had registered 14 children in total, most of them through false documents, enabling them to claim state benefits.
Late on Monday, Athens mayor George Kaminis sacked the head of the city's birth registries department, where Maria had been recorded in 2009.
"The case has exposed shortcomings at all levels," Kaminis said, noting that post-dated child registrations had multiplied eight-fold from 2011.
"One can speculate that a great number of these cases were carried out so people could claim benefits from as many sources as possible," Kaminis said.
Athens received its first international bailout in 2010 over its spiralling debt crisis and Greeks' purchasing power plummeted, plunging thousands of families into poverty.
Child trafficking ring?
There are more than 40 pending cases on the trading of minors and illegal adoptions in Greece, some of them implicating doctors and private clinics, according to justice ministry data made public on Monday.
Police were also investigating hospitals and childcare agencies for possible child trafficking, suspecting a ring operating between Greece and neighbouring Bulgaria.
In January 2011, police arrested more than a dozen people in the two countries, for the trafficking of newborn babies to Greece.
In that case it was Roma babies who were being trafficked. The ring arranged for pregnant Bulgarian women, primarily of Roma origin, to give birth in Greece before their babies were then sold off in illegal adoption procedures.
Illegal adoption, in some cases involving trafficked children, has flourished in Greece, where birth rates are low and official adoption procedures gruelling.
Intermediaries can charge €15 000-20 000 per child, the state-run Athens News Agency said on Monday, quoting police data.
Impoverished Roma families in Bulgaria are approached by traffickers who offer to pay €3 000 for a boy and €2 500 for a girl, the agency said.