On Tuesday Hamas accused Israel of exerting pressure on the head of a UN commission investigating possible war crimes by Israeli forces during last year's military offensive in the Gaza Strip.
Canadian international law expert William Schabas resigned after Israel accused him of a "conflict of interest," the United Nations announced earlier Tuesday.
"This confirms that Israel is carrying out organized terrorism which affects anybody who tries to reveal the truth and thus sue Israeli leaders in international forums," said Hamas spokesman Fawzi Barhoum in a statement.
Schabas sent a resignation letter to the head of the UN Human Rights Council on Monday after Israel accused him of having a "conflict of interest," said council spokesman Rolando Gomez.
In his letter, Schabas explained that Israel's complaint was linked to a brief legal opinion he had prepared for the PLO in October 2012.
"The complaint about my brief consultancy, as I understand it, is not about the content, which is of a technical legal nature, but the implication that in some way I am henceforth beholden to the Palestinian Liberation Organization," he wrote.
While flatly rejecting that, Schabas said that "under the circumstances and with great regret, I believe the important work of the commission is best served if I resign with immediate effect."
Gomez told reporters in Geneva that the president of the Human Rights Council had "accepted the resignation of Professor Schabas and thanks him for his work over the past six months as chair of the commission."
"The president respects the decision of Professor Schabas and appreciates that in this way even an appearance of conflict of interest is avoided, thus preserving the integrity of the process," he added.
Gomez said the commission was in "the final phase of collecting evidence" about the summer war in Gaza, and that the president stressed "the need to remain focused on the substantive work of the commission in the interest of the victims and their families on both sides."
Israeli Prime Minister Benjamin Netanyahu, meanwhile, called for the inquiry to be scrapped.
"After the resignation of the committee chairman who was biased against Israel, the report that was written at the behest of the UN Human Rights Council - an anti-Israel body, the decisions of which prove it has nothing to do with human rights - needs to be shelved," Netanyahu said in a statement.
"This is the same council that in 2014 made more decisions against Israel than against Iran, Syria and North Korea combined," he added.
The Gaza conflict ended with a truce on Aug. 26 after the deaths of more than 2,140 Palestinians, most of them civilians, and 73 Israelis, mostly soldiers.
The commission, which is scheduled to present its findings to the Human Rights Council next month, could announce the appointment of a new chair as early as Tuesday, Gomez said.
The council, the UN's top rights body, appointed Schabas as head of the three-member investigation team after the conflict ended last August, in a move that angered Israel.
"Given Mr Schabas's clear and documented bias against Israel ... his initial appointment was completely improper and pointed to the one-sided tainted and politicized nature of the commission and its mandate," Israel said in a letter to the president of the council last week.
Multiple human rights groups, including Amnesty International, Human Rights Watch, and B'Tselem, among others, have accused Israel's military of committing war crimes during the offense on Gaza.
