A British woman has been found guilty of taking her toddler son to join the Islamic State group, becoming the first woman to be convicted after returning to the U.K. from the self-declared caliphate in Syria.

Tareena Shakil was arrested last February on suspicion of Syria-related terrorism offenses and child neglect after arriving at Heathrow airport with her son on a flight from Turkey. The son has since been taken into social care.

During her trial the 26-year-old denied the charges, claiming she only travelled to Syria because she wanted to live under strict Islamic law.

But the jury did not believe her account after seeing tweets and messages in which she called on others to "take up arms."

Some 60 British women are believed to have left for Syria.