Three teenage girls from suburban Denver have been caught by the FBI trying to join the so-called Islamic State of Iraq and the Levant (ISIL) terrorist group

Three teenage girls from suburban Denver have been caught by the FBI trying to join the so-called Islamic State of Iraq and the Levant (ISIL) terrorist group.

Two sisters, aged 15 and 17, and their 16-year-old friend were apprehended at Frankfurt airport in Germany on their way to Syria.

According to their parents the girls said they were ill on Friday morning and stayed off school. They then stole $2,000 from their families and headed for Denver airport.

The two sisters are of Somalian decent and their friend is of Sudanese descent.

An FBI spokeswoman in Denver said: "The juveniles are safe and reunited with their families."

Police believe the teenagers were in contact with someone in Germany and are analysing their computers. They were at the airport in Frankfurt for a whole day.

Six months ago another teenager Shannon Conley, 19, was arrested at Denver airport on her way to join ISIL.