COPENHAGEN, Denmark –  Danish authorities have opened criminal cases against two men accused of incitement to violence by spreading jihadi videos and images online.

Police in North Zealand on Thursday arrested a 21-year-old Dane accused of spreading “extremist video material” on the Internet. Investigators say the suspect had been under surveillance since returning from Syria, where he had traveled in 2013.

In a separate case, a Copenhagen court on Thursday issued a detention order for a 26-year-old man who in July published Facebook photos of himself posing with severed heads, apparently in Syria. He also posted statements in support of the Islamic State group. Prosecutors said they would file an international arrest warrant for the man.

Neither suspect was identified.