Ulm, Germany (dpa) – German police have arrested three men on suspicion of giving money to and planning to join the ranks of the Islamic State extremist group, prosecutors said Wednesday.

Prosecutors in the southern German city of Stuttgart said the men – aged between 20 and 25 – had been detained in and around the city of Ulm on Sunday to prevent them from travelling to Islamic State-held territories in the Middle East.

A statement said that the men appeared before a magistrate on Monday and were remanded in custody, and that their apartments had been searched for evidence.

Germany is one of several western European countries concerned about its citizens – often with a Muslim immigrant background – joining Islamist insurgencies in other countries and later posing a security risk at home.