An unmanned aircraft of the sort Israel uses for surveillance and missile strikes in Gaza crashed in the south of the territory early on Tuesday, sources on both sides said.

"A Sky Rider drone crashed in the southern Gaza Strip due to a technical malfunction," an Israeli army spokeswoman told AFP. "An investigation is under way."

The Al-Rai news agency, run by the territory's Islamist rulers, Hamas, said the drone came down east of the southern city of Khan Yunis.

Hamas's armed wing, the Ezzedine al-Qassam Brigades, said its fighters had retrieved the drone.

The incident was followed by an Israeli air strike, also east of Khan Yunis, which killed three Islamic Jihad fighters, the militant group said.

It was unclear if the two incidents were related.