FROM a bare house in the small Turkish town of Reyhanli, half an hour’s drive from the border with Syria, a bearded 30-year-old with glasses claims to command a fighting force of 1,820 men who have infiltrated north-western Syria. His group, which goes by the name “Strangers for a Greater Syria”, wants the country, once it is shorn of President Bashar Assad, to become an Islamic state under Sunni rule. On a table in front of him sit pots of ammonium, potassium carbonate and phosphate, bomb-making ingredients. “We won’t impose anything,” he says. “But I think most Syrians want Islamic law.” Towns and villages along Turkey’s long border with Syria have for months been havens for an influx of Syrian rebels and refugees. Some fighting units now rotate, to let the exhausted and the wounded come and go. A small but burgeoning number of Syrian Islamists and foreign fighters are using transit points to cross from Turkey, especially since the battle for Aleppo, Syria’s second city, began in late July. Some call themselves Salafists, disciples of a puritanical version of Islam that harks back to the Prophet Muhammad’s original comrades, to attract money from rich religious networks in Turkey, the Gulf and farther afield. The leader of the “Strangers for a Greater Syria” brigade says they have nothing against other sects, including Mr Assad’s Alawites. But other Salafist groups, such as Jabhat an-Nusra (Salvation Front) and Ahrar al-Sham (the Liberation of Greater Syria), are less tolerant. At least 300 foreign fighters are thought to have trickled into the largely liberated north-western province of Idleb. Others have crossed into the eastern plains of Syria, near the rebellious city of Deir ez-Zor, an hour’s drive from the border with Iraq. Libyans and other Arabs have been spotted, along with smaller numbers of British Muslims, Pakistanis and Chechens. The black banner of jihadist groups, including those that identify with al-Qaeda, has been sighted.

Some of Mr Assad’s opponents fret that their revolution may be hijacked by extremists. It is unclear how much the jihadists co-operate with other groups. But more secular-minded leaders in the Free Syrian Army (FSA), the largest umbrella group, are wary of losing influence to them. Some FSA commanders recently tried to expel a clutch of foreign jihadists who kidnapped a British and a Dutch journalist and held them for a week. Mustafa Sheikh, a defector who heads the FSA’s top military council, says 60% of the fighters striving to overthrow Mr Assad’s regime come under the FSA’s control. But that leaves a lot who do not. “We need money from the international community to unite the rebels and stop well-funded Islamists from expanding their influence,” he says.

The FSA groups, who say they have about 50,000 fighters against a largely conscript government force of around 280,000, are only loosely linked. “We talk of an army,” admits an FSA man. “But no one really controls the groups on the ground. There are too many of them. The culture of martyrdom means that some no longer know what they are fighting for.”

Turkish villagers near the border dub one building occupied by foreigners the “al-Qaeda House”, though the people inside it deny any connection to the network. One of its inmates, a Syrian general who recently defected from Mr Assad, says that captured soldiers should be given a fair trial if they are thought to have committed atrocities. But he is angrily interrupted by a young Sunni from Latakia, a port in the Alawite heartland. “The killing will not stop when Assad falls,” he shouts. “We will kill all those who stood by the regime—and not just Syrians.”