An Alabama family is devastated after their 20-year-old daughter was recruited to join the Islamic State (IS) in November.

The woman, identified only as Hoda, left her home in a Birmingham suburb and flew to Syria, her family announced Monday.

Hassan Shibly, a spokesman for the family, said that Hoda was recruited over the internet and the family began to see a change in her about a year ago.

"The reason she withdrew from the community is because the Muslim community is very vocal against groups like ISIS," he said. "She made the decision based on her communication online with them that she wanted to join them."

Shibly, an attorney and chief executive director for the Florida chapter of the Council on American-Islamic Relations, said that the Muslim family and the Birmingham Islamic Society have denounced the terrorist group.

Hoda's family has been working with law enforcement in order to find her and bring her home. Shibly said they are "extremely traumatised" by the situation.

"For them this is worse than losing the life of a child, to have them join such a horrible, horrible gang of violent extremists," he said, adding that the mother's health has been affected. "Nothing can describe the pain they are facing."

About 500 UK citizens, 300 Germans, 150 Australians, and over 100 Americans have joined the extremist Muslim group in Iraq and Syria, according to the International Center for the Study of Radicalisation at King's College London.

Shibly said the draw for young people is similar to that of street gangs.

"It's often young, naive, impressionable, ignorant troubled youth who are dissatisfied with their life and are seeking a sense of belonging," he explained.