At least four bombings rocked Gaza City early Sunday, targeting cars belonging to officials from Islamic factions, including the territory's Hamas rulers. There were no fatalities from the blasts.

There was no claim of responsibility, but speculation immediately centered on supporters of the Islamic State group (ISIS), who have been battling with Hamas and other Islamic groups in the small coastal strip.

Hamas recently launched a fierce crackdown on alleged Islamic State supporters. Witnesses said a freshly painted ISIS flag was seen at the site of the explosions.

The charred vehicles were parked outside the houses of the local officials in Gaza City's Sheikh Radwan neighborhood. Witness Khader Mahmoud said the blasts occurred seconds apart from each other just after 6 a.m.

Ayman Sahabani of Gaza City's Shifa hospital said the blasts slightly wounded a young woman and a man.

The Hamas-run Interior Ministry said an investigation had been launched.

Extremists in Gaza inspired by ISIS have attacked Hamas positions in the past and also have fired rockets at Israel in an attempt to undermine Hamas by violating the cease-fire between Israel and Hamas that followed last year's war. The extremists believe Hamas is soft on Israel and has failed to properly establish Islamic rule in the territory.