Law enforcement agencies announced separate terrorism-related arrests this week involving suspected operatives from different extremist organizations.

In Greece, authorities arrested a suspected Hamas operative on the island of Crete who allegedly had been plotting an attack targeting an Israeli cruise ship. The individual had reportedly been granted asylum in Greece prior to the arrest. Greek officials have not released additional details about the specific nature of the alleged plot or timeline of the investigation.

Separately in the United States, the Department of Justice announced Friday that three American citizens were arrested on charges related to plotting support for the terrorist organization ISIS. Two of the suspects are from California, while the third is from Kansas.

The arrests represent ongoing counterterrorism efforts by international law enforcement agencies targeting suspected operatives from multiple extremist organizations. Both Hamas and ISIS are designated as terrorist organizations by the United States and European Union.

Authorities have not indicated any connection between the arrests in Greece and the United States. The investigations appear to involve separate plots and different terrorist organizations operating independently.