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Israeli Prime Minister Benjamin Netanyahu declared Thursday that a new agreement between rival Palestinian factions Hamas and Fatah is "killing peace," even as U.S. Secretary of State John Kerry voiced hope that talks could be salvaged.

The Israeli leader spoke with Fox News shortly after the Israeli government cut off Mideast peace talks. The Israelis halted negotiations over the announcement that terror group Hamas and Fatah would seek reconciliation.

In an interview with Fox News' Bret Baier, Netanyahu stated that peace talks are "essentially buried" if Palestinian Authority President Mahmoud Abbas forges ahead with the agreement.

"It's a blow to Israel; it's a blow to peace," he said. "It's a terrible blow to the Palestinian people, because they must choose, too, whether they want to go forward or go backward. Yesterday, with the pact with Hamas, the Palestinian people went, took a huge step backward, away from peace, away from a good future for themselves."

The grim comments seemed at odds with the tone taken in Washington by Kerry. He said the U.S., even now, isn't ready to write off Mideast peace negotiations.

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"There is always a way forward," Kerry told reporters in brief remarks at the State Department. He noted Israeli and Palestinian leaders need to make necessary compromises, without which peace "becomes very elusive."

But the "blow" to peace talks comes ahead of an April 29 deadline, and Netanyahu described the Fatah-Hamas unity agreement as a deal-breaker. The pact is undoubtedly a major setback for Kerry, who tried anew to restart the peace process after taking the reins at the State Department.

"If [Abbas] continues with the pact with Hamas, he's essentially buried it," Netanyahu told Fox News, calling Hamas "one of the preeminent terrorist organizations of our time."

The Hamas-Fatah unity plan is meant to end a seven-year rift between the rival factions. But Israel objects to any participation in Palestinian politics by Hamas, an Islamic militant group sworn to Israel's destruction. The group has killed hundreds of Israelis in suicide bombings and other attacks over the past two decades.

Netanyahu, in the interview with Fox News, stressed that history when asked about Palestinian statements that he is using the pact as an excuse to back out of peace talks.

"They can do intellectual somersaults from here to eternity, but it doesn't change the fact that they chose to make a pact with the people committed to our destruction, and that doesn't square away with peace," Netanyahu said. He said Hamas has "not relented one bit on their terror activities."

Over the last month, both sides in the troubled talks have each taken unhelpful steps and caused setbacks that have signaled an impending collapse of the negotiations. That has forced Kerry to divert focus from crises across the world, including in Ukraine and Syria, in his quest to shepherd through a Mideast peace agreement that has foiled U.S. diplomats for years.

State Department spokeswoman Jen Psaki said Kerry spoke privately with Abbas and expressed his disapproval of the plans to create a reconciliation government with Hamas, which is considered a terrorist organization by the U.S., European Union and other nations.

The negotiating period had been scheduled to expire next Tuesday. After nine months of fruitless talks, the sides had been meeting in recent weeks in hopes of extending the negotiations.

It was not immediately clear how long the U.S. is now prepared to let the latest impasse continue. U.S. negotiators will remain in the region for the time being, Psaki said.

In Washington, Sen. Lindsey Graham, R-S.C., blasted the Palestinian Authority as well as the Obama administration over the developments.

"The decision by the Palestinian Authority to align with Hamas makes any future peace negotiations with Israel impossible," he said. "This is a provocative act by the Palestinian Authority which runs counter to serious peace negotiations with Israel. It clearly demonstrates the Palestinians have little fear or respect for the Obama Administration."

Israel already halted transferring tax and customs money it collects on the Palestinians behalf, worth some $100 million a month. Those funds help keep Abbas' self-rule government afloat.

Abbas won assurances in recent Arab League meetings that Arab countries would pay $100 million to the Palestinian Authority if Israel freezes the monthly transfers. However, some of the Arab donor countries have in the past not met their aid commitments.

Saeb Erekat, the chief Palestinian peace negotiator, said Palestinian reconciliation is an internal matter.

"Israel had no right to interfere in this issue," he said. He condemned any possible Israeli sanctions as "piracy," saying the tax revenues are Palestinian money.

In the interview with Fox News, Netanyahu also reacted to Iran recently winning a seat on a human rights committee of the United Nations.

"I suppose I could imagine a greater farce but I'm not sure I'm able to do that," Netanyahu said. "I think Iran and human rights are -- it's an oxymoron."

The Associated Press contributed to this report.