President Obama’s Middle East envoy sought Tuesday to allay fears here of a fundamental breakdown in Israeli-American relations while alluding to abiding differences over Israeli settlement building in the West Bank and the formula for Israeli-Palestinian peace.

After meeting with Israeli leaders in Tel Aviv and Jerusalem, the American envoy, George J. Mitchell, said it was “beyond any doubt that the United States’ commitment to the security of Israel remains unshakeable.” But he also pressed for a peace effort, saying that Israelis, Palestinians and other parties “share an obligation to create the conditions for the prompt resumption and early conclusion of negotiations.”

Mr. Mitchell, a former Senate majority leader who helped to forge a peace deal in Northern Ireland, came to Israel amid a rare public dispute over settlement activity. The Obama administration has called for an unequivocal halt to all settlement activity. Israel’s hawkish prime minister, Benjamin Netanyahu, says there will be no new settlements but insists that building within existing ones should be allowed.

Israeli officials said they had understandings with the Bush administration that allowed for limited building. The Obama administration has not acknowledged any such understandings.

There has also been friction over Mr. Netanyahu’s refusal so far to endorse the notion of an independent Palestinian state alongside Israel. The Obama administration has said that the two-state solution is the only route to Israeli-Palestinian peace.

On Tuesday, Mr. Mitchell, who met with Israel’s president, prime minister, foreign minister and defense minister, made only oblique reference to the dispute. In his meeting with President Shimon Peres, whose post is largely ceremonial, he said Israelis and Palestinians “have a responsibility to meet their obligations under the road map,” the 2003 plan for the creation of a Palestinian state as a way to end the Middle East conflict. The plan called for Israel to stop all settlement activity and for the Palestinians to dismantle terrorism networks, reform their political institutions and curb any incitement to violence.

“It’s not just their responsibility,” Mr. Mitchell said, according to remarks released by Mr. Peres’s office. “We believe it’s in their security interest as well.”

But he added: “Let me be clear. These are not disagreements among adversaries. The United States and Israel are and will remain close allies and friends.”

Mr. Mitchell also referred to Israel as the “Jewish state” in a nod to Mr. Netanyahu, who says that Palestinian recognition of Israel as a Jewish state is essential for any peace deal. The Palestinians have refused such recognition, saying that it would contradict the Palestinian refugees’ demand for a right of return and that it is detrimental to the status of Israel’s Arab citizens.

Mr. Netanyahu has announced that he will soon make a much-anticipated major policy speech on his plans for achieving peace and security. The speech is being described here as a response to Mr. Obama’s landmark address in Cairo last week. There has been much speculation in the Israeli news media about whether the prime minister will move closer to endorsing the two-state principle.

Mr. Netanyahu said he told Mr. Obama of his intention to lay out his policies during a telephone conversation on Monday. Mr. Obama said that he was “looking forward” to hearing the speech, according to the prime minister’s office and the White House. The White House said the conversation was “constructive.”

While the Israeli leadership does not speak in one voice on all issues — the more dovish Mr. Peres and the defense minister, Ehud Barak, of the center-left Labor Party, have long favored the two-state solution — there has been a certain uniformity regarding the settlements.

Mr. Peres told Mr. Mitchell on Monday that “a two-state solution based on the road map” and “independence for the Palestinians” were important points that “needed to be emphasized en route to peace.”

On the settlements, Mr. Peres said there was agreement in Israel regarding the evacuation of illegal outposts and not building new settlements. But he said the issue of “natural growth in the settlement blocs must continue to be discussed intensively in order to reach agreement” with the American administration.

Mr. Mitchell was expected to meet with Palestinian leaders in the West Bank on Wednesday. Underlining the schism between the Western-backed Palestinian Authority there and Hamas, the Islamic militant group that controls Gaza, Agence France-Presse reported that the Palestinian police in the northern West Bank recently arrested six Hamas members, including at least two women, suspected of planning acts against the Palestinian Authority and that the police seized more than a million euros, or about $1.4 million, from them.