Gaza Medics said a second militant was also killed in the strike. The after-dark attack targeted the two men who were riding a motorcycle in the northern town of Jabaliya.

The interior ministry of Hamas, the Islamist group that controls Gaza, said one of the men killed was Hisham Al-Saedni, also known as Abu Al-Waleed Al-Maqdissi, believed to head the Jihadist Salafigroup Tawhid and Jihad (One God and Holy War).

Sources from Tawhid and Jihad could not be reached to confirm that Saedni was killed.

The group, rival to Hamas, has an Islamist ideology shared by al Qaeda and sources have said that Saedni joined al Qaeda in Iraq at the beginning of the U.S.-led invasion in 2003.

In March 2011 Hamas detained Saedni for 17 months and had freed him in August.

Last year members identifying themselves with Tawhid and Jihad kidnapped and killed a pro-Palestinian Italian activist, Vittorio Arrigoni, in an apparent attempt to secure the release of Saedni.

An Israeli military spokesman could not confirm Saedni was the target of the air strike. A written military statement said the two men targeted were "terror operatives of the Shora Council of the Mujahideen, a Gaza-based Global Jihad affiliate."

The same group had claimed responsibility for a rocket that was fired into Israel on Friday and landed near a house in the Israeli town of Netivot, causing damage but no casualties.

In response, a few hours later, the Israeli military launched three air strikes against what it said were "terror activity sites". There were no casualties reported in those attacks.

Israel says it holds Hamas responsible for any attacks launched from Gaza, which has been under the group's control since 2007. An Israeli military spokesman said that about 40 rockets were fired from Gaza into Israel in October.

Hamas rejects permanent peace with Israel and the two sides fought a three-week war in December-January 2008-2009. The border is tense, with frequent clashes.

A number of Jihadist Salafi groups have surfaced in Gaza in recent years. Unlike Hamas, they endorse an ideology of global Jihad and some accuse Hamas of failing to implement Islamic laws in the coastal enclave.