The three girls captured on CCTV in Gatwick airport.. Pic: Metropolitan Police

The three missing Muslim schoolgirls from Bethal Green waited in an Istanbul bus station for more than 18 hours before catching a bus that took them towards Syria, new CCTV images reveal.

On February 17 they boarded a plane Istanbul, where CCTV footage now shows the girls in a waiting room at Bayrampasa bus station for nearly 18 hours, according to time stamps on the video.

According to the BBC, the girls then boarded a bus that took them to Urfa, close to the Syrian border.

The information follows an announcement by the Metropolitan police last week that they had reason to believe the girls have crossed the border into Syria.

It has been two weeks since Shamima Begum, Amira Abase and Kadiza Sultana flew from Gatwick to Istanbul, after leaving their homes on what was supposed to have been a normal day.

Last week, it was reported that the girls were seen on CCTV footage in Gatwick about to board a Turkish Airline flight, TK1966, towards Istanbul.

Since CCTV images placed the girls at Gatwick Airport, The Metropolitan Police have worked closely with Turkish authorities and they have provided “great assistance and support to the investigations”.

The girls are believed to have crossed the Syrian border near Kilis with the help from people smugglers.

The girls’ families have made emotional appeals for them to come home.

BBC’s James Reynolds in Gaziantep was told by a source, claiming to be people smuggler, that the girls were driven from Urfa to the Syrian border, where they walked across to the other side on their own.

The source told Reynolds that a group of IS men were waiting for the girls and picked them up with cars immediately after they crossed the border.