A video purportedly showing three British schoolgirls moments before they were smuggled by an alleged foreign spy from Turkey into Syria - where they joined the Islamic State (Isis) terror group - has emerged.

Three girls, said to be runaway London teenagers Shamima Begum, Kadiza Sultana and Amira Abase, are seen in the shaky footage as they unload their baggage from a taxi and enter another vehicle in what appears to be Turkey's southern city of Gaziantep.

They are helped by two men, one of whom is filming the operations with a mobile device. The man asks the girls their names and then helps them into another vehicle, saying it will take them across the border within one hour.

Speaking in English, he tells the girls not to forget anything, including their passports. "It's nice!" he is heard saying in the clip obtained by broadcaster A Haber.

He then wishes them good luck, adding he will not personally accompany them to the border as he will return to Sanlıurfa a Turkish about 50km north of the Syrian city of Kobani.

The smuggler was arrested earlier in March by Turkish authorities who claimed he was an intelligence officer working for an anti-IS coalition member state.

In a separate video also published by A Haber, the suspect is seen living a courthouse in Turkey flanked by plain clothed security agents.

"It turned out to be someone who worked in the intelligence services of a country in the coalition," Turkey Foreign Minister Mevlut Cavusoglu said announcing the arrest.

The minister did not reveal the nationality of the agent but said they did not work for the US or any EU state. Turkish media claimed he was a Syrian national working for the Canadian Security Intelligence Service (CSIS), named as Mohammed al Rashid.

Canadian government sources denied the man was employed by CSIS or any other federal agency.

However, Reuters quoted a European security source familiar with the case as saying the suspect had ties to the CSIS.

A spokesperson for Canada's Public Safety Minister, Steven Blaney, told The Toronto Star: "We are aware of these reports. We do not comment on operational matters of national security."

Begum, 15, Sultana, 16, and 15-year-old Abase flew from London's Gatwick Airport to Istanbul on 17 February. CCTV images appeared to show the teenagers boarding a bus to Gaziantep, a notorious port of entrance for foreign fighters travelling to Syria. They are now believed to be living in IS's de facto capital, Raqqa.

The Turkish government has been criticised by its Nato allies for allegedly not doing enough to prevent would-be-jihadists from crossing its long and porous border with Syria. In turn, Ankara claimed Western states have failed to provide it with enough intelligence on suspect travellers.

Thousands of Westerners have travelled to IS-held territories via Turkey, swelling the terror group ranks over the past two years.