Samra Kesinovic was just 16, and her friend Sabina Selimovic, 15, when they vanished earlier this year from their homes in the Austrian capital Vienna and then posted images of themselves brandishing Kalashnikov rifles, and in some cases surrounded by armed men.

Now police are concerned the girls had become the public face for the call to jihad in Syria after two teenage girls also from Austrua fled to take up the call for holy war.

This time the pair were stopped as they attempted to leave the country to travel to Syria to join the Islamic State (Isis) jihadists.

Little information was given about the latest two girls apart from the fact that one was 16 and the other was 14.

Police are now hoping to find out how they became radicalised, and whether anybody had helped them plan their trip to Syria which was apparently set to take place via Turkey - following the same route as the other two girls.

The pair were caught when the mother of a third friend who was supposed to be travelling with them became suspicious about the amount of luggage her daughter was packing.

As many as 130 people from Austria are now believed to be fighting as jihadists abroad.

More than half of Austrian's jihadists originally come from the Caucasus region and have a valid residence permit in Austria.

Austrian Interior Ministry spokesman Alexander Marakovits said they were noticing an increasing problem with youngsters wanting to leave the country for the same reason.

He said: "If we can catch them before they leave we have the chance to work with their parents and other institutions to bring the youngsters out of the sphere of influence that prompted them to act in this way the first place.

"Once they have left the country, even if they then changed their minds, it is then almost impossible to get them back."