JERUSALEM - A pair of testy public exchanges last week appear to have undone whatever good will was created between the Israeli and U.S. governments during a high-profile visit by President Obama early this year.

Tensions burst into the open during a swing through the region by Secretary of State John Kerry. In an interview broadcast on both Israeli and Palestinian TV, Kerry questioned Israel's seriousness about peace with the Palestinians. Hours later, Prime Minister Benjamin Netanyahu fired back, vowing not to cave in to concessions to the Palestinians - and also saying he "utterly rejects" an emerging nuclear deal between world powers and Iran.

The rancor signals a tough road ahead for the twin American goals of finding a diplomatic solution for Iran's nuclear program and forging peace between Israel and the Palestinians. And it raises the specter of a return to the uncomfortable relationship that has often characterized dealings between Obama and Netanyahu.

Israeli news reports describe Netanyahu as being in "shock" over the possible Iranian compromise. Netanyahu, who sees Iran as an arch-enemy, has vowed to do anything, including a military strike, to prevent Iran from reaching weapons capability.

Obama and Netanyahu took office just months apart in 2009, but seemed to have little in common. At joint appearances they appeared uncomfortable and even occasionally sparred.

The lack of chemistry seems rooted in vastly different worldviews. Obama is a proponent of diplomacy and consensus, while Netanyahu believes Israel can trust no one and must protect itself.

And there has been constant friction over Netanyahu's insistence on continuing to settle Jews on occupied land even as he negotiates with the Palestinians.

Over the summer, Kerry persuaded Israel and the Palestinians to return to the negotiating table for the first time in nearly five years. To get talks going, Palestinians dropped a demand for an Israeli freeze on settlement construction in the West Bank and East Jerusalem, captured territories that Palestinians claim for a future state. To get Palestinians back to talks, Israel committed to releasing 104 long-serving Palestinian prisoners. The U.S. apparently gave vague assurances settlement construction would be restrained.

With negotiations making no visible progress, Israel's release of a second round of Palestinian prisoners two weeks ago - all jailed for killing Israelis - set off an uproar. Netanyahu followed the release by announcing plans to build thousands of settler homes, infuriating the Palestinians, the Americans, and the moderate camp in Israel itself.

Kerry told Israel's Channel 2 TV on Thursday that Israel faced the possibility of international isolation and renewed violence with the Palestinians if peace efforts failed. He also said continued settlement construction raised questions about Israel's commitment to peace. Netanyahu responded the next morning. "No amount of pressure will make me or the government of Israel compromise on the basic security and national interests of the State of Israel," he said.

The two had a tense meeting that stretched more than two hours, and a planned joint appearance to the media was canceled.