Poland's Internal Security Agency (ABW) has detained a Russian citizen accused of being a member of ISIS, the National Prosecutor's Office said in a statement on Thursday.
"The prosecutor... charged the detainee with being part of armed groups in the Syrian Arab Republic aimed at committing crimes of a terrorist nature," the prosecutor's office said in a statement.
It said that the accused had been a part of Jabhat Al-Nusra and al-Qaeda before joining ISIS.
The man is being held in pre-trial detention for three months and if found guilty could face eight years in prison.