High Court judge Anthony Hayden made the 15- and 16-year-olds wards of court, which prevents them from leaving England and Wales. He also ordered their passports removed.
The judge said today that the measures were "draconian," but added, "sometimes the law has to intervene to protect these young people, ultimately from themselves."
Authorities are making increasingly strenuous efforts to stop young Britons, including boys and girls as young as 15, trying to reach areas of Syria controlled by Islamic State militants.