Germany's Cabinet on Wednesday approved a plan to allow authorities to withdraw identity cards from Islamic extremists and prevent them from traveling to Iraq, Syria or other crisis areas to join terrorist groups.

The plan has been in the works since October and still requires parliamentary approval. It would allow authorities to withdraw plastic national identity cards for up to three years. Those affected will get a replacement temporary identity card stating in several languages that it doesn't entitle the holder to leave Germany.

It is already possible to withdraw passports but officials until now have lacked the authority to withhold the identity cards that Germans use to travel to many countries in and beyond the European Union — among them Turkey, through which the vast majority of extremists who went from Germany to Syria and Iraq are believed to have traveled.

Interior Minister Thomas de Maiziere said that around 600 suspected extremists from Germany are now believed to have left the country — up from the 550 that officials previously said had traveled to Syria and Iraq to join extremist groups.

"There is no panacea against terror, but we have an obligation to do everything in our power to reduce the danger of terrorist attacks and of Germans participating in them at home and abroad," de Maiziere said. He said he couldn't predict how many people the new rules might affect.