* French surgeon returns after 2 weeks in Aleppo hospital
* Says French fighters inspired by Toulouse gunman Merah
* Says Turkey flooding parts of border to stop refugees
By John Irish
PARIS, Sept 8 Foreign Islamists intent on turning Syria into an autocratic theocracy have swollen the ranks of rebels fighting to topple President Bashar al-Assad and think they are waging a "holy war", a French surgeon who treated fighters in Aleppo has said.
Jacques Beres, co-founder of medical charity Medecins Sans Frontieres, returned from Syria on Friday evening after spending two weeks working clandestinely in a hospital in the besieged northern Syrian city.
In an interview with Reuters in his central Paris apartment on Saturday, the 71-year-old said that contrary to his previous visits to Homs and Idlib earlier this year about 60 percent of those he had treated this time had been rebel fighters and that at least half of them had been non-Syrian.
"It's really something strange to see. They are directly saying that they aren't interested in Bashar al-Assad's fall, but are thinking about how to take power afterwards and set up an Islamic state with sharia law to become part of the world Emirate," the doctor said.
The foreign jihadists included young Frenchmen who said they were inspired by Mohammed Merah, a self-styled Islamist militant from Toulouse, who killed seven people in March in the name of al-Qaeda.
Assad himself has consistently maintained that the 17-month-old insurgency against him is largely the work of people he refers to as "foreign-backed terrorists" and says his forces are acting to restore stability.
During his previous visits to Syria - in March and May - Beres said he had dismissed suggestions the rebels were dominated by Islamist fighters but he said he had now been forced to reassess the situation.
The doctor's account corroborates other anecdotal evidence that the struggle against Assad appears to be drawing ever greater numbers of fellow Arabs and other Muslims, many driven by a sense of religious duty to perform jihad (holy war) and a readiness to suffer for Islam.
But while some are professional "jihadists", veterans of Iraq, Afghanistan, Chechnya or Libya who bring combat and bomb-making skills with them that alarm the Western and Arab governments which have cheered the rebels on, many have little to offer Syrians but their goodwill and prayers.
Beres described treating dozens of such jihadists from other Arab countries, but also at least two young Frenchmen.
"Some of them were French and completely fanatical about the future," he said. "They are very cautious people, even to the doctor who treated them. They didn't trust me, but for instance they told me that Mohammed Merah was an example to follow."
Merah tore a wound in France's fragile sense of community in March when he gunned down three soldiers from North African immigrant families, a rabbi and three Jewish children.
Paris has for several years been concerned that French radical Islamists who have travelled to lawless zones would return to plot attacks at home. Merah had travelled to Afghanistan and Pakistan to receive training.
On his previous trips he worked in makeshift hospitals, but this time Beres said he received as many as 40 injured people each day in a normal hospital that was under rebel control in the economic hub Aleppo.
He said he had treated civilians who had been queuing for bread at a market place when it had been shelled.
"The baker was killed. He was a thin man completely covered in white flour with shrapnel holes and blood all over. It was a striking and troubling image," he said.
"What people have to know is that the number of dead is a far cry from what's been announced. I'd say you have to multiply by two to get the real figure."
The Syrian Observatory for Human Rights says that more than 23,000 people have been killed in the uprising. More than 200,000 Syrians have fled to neighbouring Turkey, Jordan, Iraq and Lebanon.
Beres, who entered Syria via Turkey's northern border, said he had also seen signs that Ankara was trying to stop Syrians crossing the border.
Showing his muddied surgical case, shoes and clothes, Beres said that Turkish forces had flooded the Reyhanli border area with water making it difficult for refugees to cross unnoticed.
"We were caught by the Turkish army. It took us 20 hours to cross the border and I was fined $500 for crossing the border illegally. They flooded the border completely so that they can hear who is crossing. Those they do catch they are sending back," he said.