At one stage the British government did try something similar. They called it internment, dtention without cause or trial, rounded up all the young men, put normal folks beside the actual terrorists, and componded the problem by increasing the recruiting ranks considerably.
Awful idea, worked terribly, and notably bolstered resentment against Britian and swelled the IRAs ranks.
They clearly need to do some control over immigrants, but internment wouldn't help.
bombing/invading syria wouldn't help either, all this hatred of the west has come from the cluster **** that was iraq and afghan