US Secretary of State Hillary Rodham Clinton raised the stakes in a growing rift with Israel, calling its announcement of provocative settlement-building plans during the visit of Vice President Joe Biden "insulting."
Her remarks to CNN late Friday followed her 43-minute delivery of "strong objections" earlier in the day to Israeli Prime Minister Benjamin Netanyahu, DPA reported.
In other criticism of Israel's plans to build 1,600 housing units in occupied East Jerusalem, the international group of mediators in the Middle East known as the Mideast Quartet condemned Israel for the plans.
The group - which consists of the European Union, Russia, the United Nations and United States - warned that the new construction could have a negative effect on Israeli-Palestinian peace talks.
Clinton told Netanyahu that Israel's building plans sent a "deeply negative signal" about Israel's attitude toward the bilateral relationship and peace efforts, a State Department spokesman said.
"The announcement of the settlement the very same day the vice president was there was insulting - an unfortunate and difficult moment for everyone," Clinton told CNN.
On Thursday, Biden sang a softer tone, balancing out his harsh criticism of the housing announcement with strong public reassurances of US "iron-clad" support for Israel and its security.
But by Friday, US President Barack Obama was still apparently enraged over the prospect that Washington's just-brokered indirect talks between the Israelis and Palestinians could unravel.
Clinton's rebuke stunned many observers and Israel supporters with its tough tone.
"We cannot remember an instance when such harsh language was directed at a friend and ally of the United States," Abraham Foxman, director of the Anti-Defamation League, said in a statement.
The administration opposes any new settlement activity in the occupied territories, and the Palestinians have demanded a halt to construction as a condition for returning to the negotiating table. After the announcement, the Palestinians threatened to withdraw from the hard-sought indirect discussions.
Clinton "made clear that the Israeli government needed to demonstrate not just through words but through specific actions that they are committed to this relationship and to the peace process," US State Department spokesman PJ Crowley said.
The Israeli government described the announcement as a bureaucratic mistake by Jerusalem's planning committee, which did not require approval from the prime minister's office before making it.
The State Department did not entirely accept that explanation.
"We accept what Prime Minister Netanyahu has said," Crowley said. "By the same token, he is the head of the Israeli government and ultimately is responsible for the actions of that government."
Obama has identified renewing the Israeli-Palestinian peace process as a top priority and his diplomatic team has invested considerably in getting it back on track. Special envoy George Mitchell has made numerous trips to the region and was scheduled to return again next week.
Meanwhile, Washington was working to contain the fallout. Mitchell and Assistant Secretary of State for Near Eastern Affairs Jeffrey Feltman have been on the phone with Palestinian President Mahmoud Abbas and the foreign ministers of Egypt, Jordan, Qatar and the United Arab Emirates to try to prevent the Palestinians from backing out of the talks.
"We jointly remain committed to this process, acknowledging that, obviously, it is a difficult environment given the Israeli statement," Crowley said.
The US-based Anti-Defamation League called Clinton's remarks a "gross overreaction" to a "policy difference among friends."
"One can only wonder how far the US is prepared to go in distancing itself from Israel in order to placate the Palestinians in the hope they see it is in their interest to return to the negotiating table," Foxman said.
In other developments Friday, Jordan's Islamic leaders joined the Lebanese Shiite movement Hezbollah in slamming the housing plans.
In Amman, the Islamic Action Front, the largest Jordanian political party in terms of member numbers, called for violent jihad against Israel at a rally in the Jordan Valley near the Jordanian border with the West Bank.
In Lebanon, Hezbollah accused the United States of backing the Israeli decision, adding, "Such a step is very dangerous and aims to change the demographics of the city."
On Thursday, Jordan's King Abdullah II met with Biden and called for an "immediate halt" to Israel's building of settlements in East Jerusalem. He said the issue was set to "torpedo" ongoing peace efforts.
Palestinians clashed with Israeli police at barricades at several East Jerusalem sites, but Friday's Muslim prayers passed relatively quietly amid tight security measures, officials said.