© photo credit: APDemonstrators chant in support of al-Qaeda-inspired Islamic State of Iraq and the Levant (ISIL) as they wave al-Qaeda flags in front of the provincial government headquarters in Mosul.
A new Palestinian jihadist group pledging allegiance to the Islamic State (formerly known as ISIL) has claimed responsibility for the killing of three Israeli teenagers last month in the West Bank, as well as other recent deadly attacks against Israeli soldiers and civilians.

In a statement posted on jihadi websites Tuesday, the Supporters of the Islamic State in Bayt al-Maqdis said it was behind the capture and killing of "the three soldiers" in Hebron (actually, it was in the nearby Etzion bloc), sniper attacks in Hebron and Tarqumia, and missile launches from Gaza into Israel a month and a half ago.

The actions were carried out in honor of Abu Bakr al-Baghdadi, the self-proclaimed "caliph" of the Islamic State, the reincarnation of the Islamic State in Syria and the Levant (ISIL) declared last month, the statement said.

"We are not a partisan group like the humiliated organizations, many of whose leaders sold their religion for the benefit of politics," the communique read, in a critique of both Fatah and Hamas.

"They have entered polytheistic parliaments and allied themselves with heathens and Shiite leaders, transferring their preaching and religion to the West Bank and Gaza, God help us."

Aaron Zelin, a Richard Borow Fellow at the Washington Institute and expert on global jihadist organizations, said he knew nothing of the group.

"It is difficult to assess whether it's legitimate," he said.

Prime Minister Benjamin Netanyahu has held Hamas responsible for the killing of Gil-ad Shaar, Naftali Fraenkel and Eyal Yifrah on June 12. On Wednesday, Hamas spokesman Sami Abu Zuhri refuted a report by Sky News Arabia claiming that the movement's political chief Khaled Mashaal had denied Hamas's involvement. Abu Zuhri said Hamas "has no information on the subject."

Israel's two prime suspects in the killing - Marwan Kawasme, 29, and Amar Abu Aysha, 32 - are both member of Hamas activists in Hebron.

The jihadist statement threatened both Israel and Palestinian Authority leaders with death and destruction.

"Our message to the Jews in Bayt al-Maqdis [the Islamic term for Jerusalem] and its environs: by occupying the land of the Muslims in Palestine ... you have opened a door that cannot be shut unless you leave [the land] humiliated ... or [are] killed, the way you found the putrid bodies of your three soldiers. We carry in our pockets black days for you.

"To the leadership of the heretic [Palestinian] Authority: We have surprises for you that will shake your thrones and end your aggression against Muslims in the West Bank and Gaza. You have killed us and and rebelled against God ... wait for us, we will come to slaughter and kill you. We shall not fail the oppressed Muslims until we free every believer from your prisons."

An unknown group named Hezbollah Brigades also claimed responsibility for the abduction last month, saying it was retribution for the 2008 assassination of Hezbollah leader Imad Mughniyeh.