The three Colorado girls, of Sudanese and Somali origin, were heading for Turkey when they were stopped by German authorities at Frankfurt airport, CNN said.
Turkey is a key point of entry for would-be jihadists looking to join Islamic State militants in Iraq and Syria.
A law enforcement official told ABC News that the girls were trying “to fulfill what they believe is some vision that has been put out on a slick media campaign” by radical groups in Syria.
Federal Bureau of Investigation spokesman Paul Bresson told AFP that the agency was “aware of the situation and assisted with bringing the individuals back to Denver on Monday.
“The juveniles are safe and reunited with their families,” he said.
Citing Arapahoe County Sheriff’s Office documents, CNN said the girls had left home with their passports and $2,000 in cash.
Their families had reported the three girls, who are aged 15, 16, and 17, missing on October 17.
The FBI spoke to the girls upon their return but the agency declined to comment further because the girls are juveniles. -AFP