Hamas police detained a suspected jihadist leader in Gaza on Saturday, a security source said, according to AFP.
"This morning, security forces arrested Nour Issa, 27, who is a leader of the deviant thought movement and is from Bureij Camp in central Gaza, along with others," the source said, using a phrase Hamas officials routinely use to refer to jihadists, including members of the Islamic State (ISIS).
The internal security service confirmed on its Facebook page that it had made a number of arrests.
"One of the leaders of the deviant thought has been arrested along with others," it said, without giving a name.
Hamas has run Gaza for a decade but it has been challenged by small hardline factions, some of them inspired by ISIS, who say there should be a stricter interpretation of Islam.
Some have carried out sporadic rocket attacks into Israel.
Salafists in Gaza in particular have clashed with its Hamas rulers, challenging what they perceive is Hamas’s moderate interpretation of Islam.
In August, a suicide bomber allegedly linked to ISIS killed a Hamas guard in southern Gaza along the border with Egypt, in a rare attack against Hamas.
Hamas security forces later raided an outpost in Gaza belonging to the Popular Resistance Committees, which is close to the Salafist movement and affiliated with ISIS.