Israel doesn’t plan to stop its Gaza Strip offensive as long as the Palestinian territory’s Hamas rulers continue to pose a threat, Justice Minister Tzipi Livni said, as U.S. Secretary of State John Kerry flew to Israel in pursuit of an elusive truce deal.

“There is no reason to stop here if Hamas continues to threaten, continues to fire,” Livni, her country’s former chief negotiator with the Palestinians, told Israel Radio. She said Israel may be headed toward an ongoing offensive “whose objective is not to contain the threat, but to disarm terror organizations, including Hamas.”

The threat reverberated across Israel’s economy yesterday after a rocket landed about a mile away from Israel’s international airport. The U.S. Federal Aviation Administration imposed a ban on flights to Tel Aviv by American carriers and the European Aviation Safety Agency recommended a suspension.

As Livni, one of the government’s most dovish ministers, spoke of the possibility of an expanding campaign, the United Nations High Commissioner for Human Rights said war crimes may have been committed in the conflict. Navi Pillay singled out Israel’s military conduct.

Hamas spurned a proposal Egypt put forward last week after Israel accepted it, saying it didn’t guarantee lifting the blockade on the Gaza Strip.

Kerry announced no breakthroughs after meeting yesterday with Egyptian officials in Cairo. Today, he flew to Israel to join United Nations Secretary-General Ban Ki-moon to press ahead with his truce mission. “We made some steps forward but there is still work to be done,” he said at a joint news conference with Ban in Jerusalem.

Kerry put the burden on Hamas, saying it has “a fundamental choice to make.”

Pillay’s allegations of possible Israeli war crimes drew a furious reaction in Israel, with Foreign Ministry spokesman Yigal Palmor accusing her of making “intolerably biased statements” based on newspaper reports.

“Her embarrassingly shallow and populist affirmations” do a “huge disservice to actual human rights,” Palmor said in an e-mailed statement.

In testimony to the UN Human Rights Council in Geneva, Pillay said not abiding by principles meant to shield civilians “may amount to war crimes and crimes against humanity.” While she criticized Gaza rocket fire for endangering the lives of Israeli civilians, most of her testimony dwelt on the Israeli military’s operations.

She criticized Israeli warnings to Gaza civilians to evacuate as insufficient. Citing accounts of Israeli attacks on houses, a center for the disabled and a hospital, she said “these are just a few examples where there seems to be a strong possibility that international humanitarian law has been violated, in a manner that could amount to war crimes.”

After Israel’s last offensive, the UN conducted a war crimes investigation and accused Hamas and Israel of potential war crimes. The panel’s head, Richard Goldstone, later said new information on the events may have produced different conclusions.