JERUSALEM — Hours after Vice President Joseph R. Biden Jr. vowed unyielding American support for Israel’s security here on Tuesday, Israel’s interior ministry announced 1,600 new housing units for Jews in East Jerusalem, prompting Mr. Biden to condemn the move as “precisely the kind of step that undermines the trust we need right now.”

Prime Minister Benjamin Netanyahu was clearly embarrassed at the move by his interior minister, Eli Yishai, head of the right-wing Shas party who has made Jewish settlement in East Jerusalem one of his central causes.

A statement issued in the name of the Interior Ministry but distributed by the prime minister’s office said the housing plan was three years in the making and that its announcement was procedural and unrelated to Mr. Biden’s visit. It added that Mr. Netanyahu had just been informed of it himself.

Mr. Netanyahu supports Jewish settlement in East Jerusalem yet wants to get new talks with the Palestinians going and to maintain strong relations with Washington. But when he formed his coalition a year ago he joined forces with several right-wing parties, and has since found it hard to keep them in line.

Mr. Biden came to Jerusalem largely to assure the Israelis of Washington’s commitment to its security and to restart peace talks with the Palestinians.

He began the day on a note of support, asserting the Obama administration’s “absolute, total, unvarnished commitment to Israel’s security.”

But by the end of the day, Mr. Biden’s tone had a very different quality. He issued a statement condemning “the substance and timing of the announcement” of the housing, and adding: “Unilateral action taken by either party cannot prejudge the outcome of negotiations on permanent status issues.” He said the announcement “runs counter to the constructive discussions that I’ve had here in Israel.”

On Monday, George J. Mitchell, the administration’s Middle East envoy announced that Israel and the Palestinians had agreed to four months of indirect peace talks, the first such negotiations in more than a year.

Nabil Abu-Rudeina, spokesman for the Palestinian government, called the new housing announcement “a dangerous decision that will torpedo the negotiations and sentence the American efforts to complete failure.” He added that “it is now clear that the Israeli government is not interested in negotiating nor is it interested in peace. The American administration must respond to this provocation with actual measures, as it is no longer possible to just turn the other cheek, and massive American pressure is required in order to compel Israel to abandon its peace destroying behavior.”

Last spring, the Obama administration tried to get Israel to stop all settlement building in order to get peace talks going again and hoped Arab states would promise confidence building measures in exchange. No such measures were forthcoming and the Israelis rejected the freeze.

After much haggling, in November the Israelis announced a 10-month partial freeze on new settlement building in the West Bank. But they specifically exempted Jerusalem from the moratorium, becayuse Israel has annexed East Jerusalem and considers it part of its united capital, something the rest of the world rejects.

The new housing announced on Tuesday was for the ultra-Orthodox neighborhood of Ramat Shlomo. The Interior Ministry statement said the step on Tuesday was part of a long process that would continue for quite some time before the units were actually built.

It followed a day in which Mr. Biden who will stay in the region through Friday, had made a concerted and highly public show of American support for Israel.

“Progress occurs in the Middle East when everyone knows there is simply no space between the United States and Israel,” he said standing next to Mr. Netanyahu at the prime minister’s residence. “There is no space between the United States and Israel when it comes to Israel’s security.”

Mr. Biden also said that, like Israel, the Obama administration was determined to prevent Iran from acquiring nuclear weapons and from supporting groups that threaten Israel. The United States is trying to build a consensus for international sanctions against Iran over its nuclear program. Israel has threatened to use military force but is going along with the American approach for now. Part of the purpose of this trip is to cement that cooperation.

Mr. Biden expressed satisfaction at the agreement over the new talks with the Palestinians. They are being billed as “proximity talks,” because Mr. Mitchell is expected to shuttle between the Israeli government in Jerusalem and the Palestinian Authority in Ramallah, West Bank to bring the two sides toward direct negotiations.

In his public comments with Mr. Biden, Mr. Netanyahu focused on the need “to be persistent and purposeful in making sure we get to those direct negotiations that will enable us to resolve this conflict.”

The announcement on the housing expansion was not the first time that Mr. Netanyahu has been blindsided by one of his more nationalist or conservative ministers or their aides. Earlier this year, for example, Daniel Ayalon, the deputy to the nationalist foreign minister, Avigdor Lieberman, increased tensions with Turkey when he humiliated its ambassador to Israel in front of television cameras.

Mr. Biden is to spend Wednesday in the West Bank meeting with Palestinian President Mahmoud Abbas and Prime Minister Salam Fayyad, then give a speech in Tel Aviv on Thursday before heading to Jordan.

After his morning meetings with President Peres and Mr. Netanyahu on Tuesday, Mr. Biden, accompanied by his wife Jill, visited the Rabin gravesite. Mr. Rabin was assassinated in 1995 by a Jewish extremist opposed to reconciliation with the Palestinians.

Mr. Biden then toured Yad Vashem, the Holocaust museum and center. After signing its guest book, he said, “The phrase ‘never again’ is used so often it almost has lost its meaning. But then again all you have to do is walk through Yad Vashem to understand how incredible the journey has been for world Jewry and why Israel is such a central part of its existence.”

Jack Healy contributed reporting from New York.