A string of car-bomb explosions has shaken Gaza City and regional concerns about security.
The vehicles belonged to members of Hamas and the Islamic Jihad, which rule the Palestinian territory.
Speculation as to who was behind the attacks quickly centred on the Islamic State of Iraq and the Levant (ISIL) group.
Hamas has been cracking down on ISIL supporters since the Syria- and Iraqi-based group threatened to topple Gaza's leaders.
A photo reportedly taken near the scene of one of the explosions appeared to show the ISIL logo.
Groups in Gaza, said to be inspired by ISIL, have been firing rockets at Israel in an apparent attempt to undermine ceasefire talks.
ISIL has accused Hamas of being soft on Israel and failing to establish Islamic rule in Gaza.
How are these latest attacks on Hamas playing into wider regional tensions?
Presenter: Adrian Finighan
Ahmad Azem - professor of international relations at Birzeit University.
Joseph Kechichian - senior writer at Gulf News.
Aymenn Al-Tamimi - a fellow at the Middle East Forum and ISIL specialist.
Source: Al Jazeera