Despite attempts to align their positions on Iran’s nuclear program, Israel and the United States were publicly at odds Monday over Prime Minister Benjamin Netanyahu’s call for Washington to set a “clear red line” beyond which it would launch a military attack.

A day after Secretary of State Hillary Rodham Clinton said the United States is “not setting deadlines” for Iran and considers negotiations the best approach, a senior Israeli official charged that “these statements won’t serve to deter Iran, but could well put it at ease.”

“Without a clear red line Iran will not cease its race toward a nuclear weapon,” said the senior official, who was not authorized to identify himself by name. “These statements will not stop Iran’s centrifuges from spinning. Unfortunately, the opposite could well be true.”

Netanyahu told an interviewer Sunday that Israel is discussing red lines with the United States. He did not say whether those discussions include any new offers from the Obama administration, but White House press secretary Jay Carney waved off that suggestion Monday.

“The president’s position, unequivocally, is that he is committed to preventing Iran from acquiring a nuclear weapon,” Carney said. “We share that view with Israel and Israel’s leadership in a way that has been made clear again and again.”

Iran has denied that it is seeking nuclear weapons, and U.S. intelligence has not detected any evidence that the leadership in Tehran has decided to build a nuclear bomb, senior Obama administration officials have said.

Netanyahu, who is traveling to the United States later this month, has been pressing the Obama administration to spell out the point at which Iran’s nuclear program could face an American military strike.

Netanyahu argues that only an ultimatum to Iran has a chance of swaying Tehran and averting a military confrontation. He has not specified what that line should be, but his demand reflects the sense of urgency projected by the Israeli leadership, which has called a nuclear-armed Iran an existential threat to Israel.

The Obama administration is arguing for more time for diplomacy and sanctions.

“We believe that there remains time and space for that effort to bear fruit,” Carney said Monday. “We’ve also made clear that the window of opportunity for reaching a solution by that means will not remain open indefinitely.”

On Sunday, Clinton appeared to rule out an ultimatum to the Iranians.

“We’re not setting deadlines,” she told Bloomberg Radio when asked whether Washington would draw “red lines” for Iran or spell out the consequences of failing to reach agreement with world powers by a certain date.

Israeli Defense Minister Ehud Barak has warned that time is running out as Iran’s nuclear facilities approach a “zone of immunity,” protected in underground bunkers invulnerable to Israeli attack.

Interviewed Sunday on Canadian television, Netanyahu said that Israel was currently in discussions with the United States on “a clear delineation of a line which Iran cannot cross in its pursuit of the development of nuclear weapons capability.”

The issue sparked a heated exchange last month between Netanyahu and Dan Shapiro, the U.S. ambassador to Israel, according to Rep. Mike Rogers (R-Mich.), who was present and gave his account last week to a Detroit radio station.

Rogers, the chairman of the House Intelligence Committee, said Netanyahu was frustrated with what he sees as a lack of U.S. resolve to draw lines for military action if necessary. Shapiro has denied the reports of a sharp exchange.

Barak said after a meeting last week with Adm. James A. Winnefeld, the vice chairman of the Joint Chiefs of Staff, that there were “differences” between Washington and Israel and that “the clock is ticking at a different pace for each of us.”

Clinton voiced a similar assessment in the radio interview. “They’re more anxious about a quick response because they feel that they’re right in the bull’s-eye, so to speak,” she said, referring to the Israelis. “But we’re convinced that we have more time to focus on these sanctions, to do everything we can to bring Iran to a good-faith negotiation.”

Dore Gold, a former U.N. ambassador who has advised Netanyahu, told Israel Radio on Monday that Clinton’s remarks meant that the United States faced “a serious problem” in stopping Iran, because of the lack of a “concrete threat” to use force.

“There are differences in approach here,” he said of the views in Jerusalem and Washington, “and they are deep.”

Anne Gearan in Washington contributed to this report.