WASHINGTON – Secretary of State Hillary Rodham Clinton sought to inject urgency into Israeli-Palestinian peace talks Friday, warning that the negotiations may be “the last chance for a very long time” to reach an agreement.

In a joint interview with Israeli and Palestinian television broadcasters a day after she presided over the launch of the first direct talks in two years, Clinton said the rise of Iranian-backed extremist ideology in the Middle East is a major reason why time is short.

Iran’s suspected nuclear ambitions have surfaced as a new motivating factor for a Mideast resolution. There have been growing Israeli warnings that the nation might take military steps to blunt Iran’s nuclear program, and even some of Israel’s Arab neighbors have shown concerns.

The administration believes that a successful Mideast peace deal would limit Iran’s ability to use Mideast tensions to justify its behavior.

“I think that time is not on the side of either Israeli or Palestinian aspirations for security, peace and a state,” she said. Iranian-sponsored “rejectionist ideology” and a “commitment to violence” by those opposed to peace make reaching an agreement quickly all the more necessary, she said.

“The United States,” Clinton said, “wants to weigh in on the side of leaders and people who see this as maybe the last chance for a very long time to resolve this.”

Shortly before the interview, Iranian President Mahmoud Ahmadinejad dismissed the peace talks, saying “the fate of Palestine will be decided in Palestine and through resistance and not in Washington.”

Iran supports the Palestinian militant group Hamas, which controls the Gaza Strip, which along with the West Bank is supposed to form an eventual Palestinian state.

The Obama administration wants a peace deal concluded within a year and both sides pledged Thursday to try to meet that goal in successive rounds of talks. Despite early positive signals from Israeli and Palestinian leaders, hopes for an agreement rest on overcoming significant obstacles and decades of hostility and suspicion.

Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas will meet for a second round of talks in Egypt on Sept. 14 and 15 and then about every two weeks while lower-level negotiations continue on ironing out specifics of compromises that both sides will have to make.

After the meeting in Egypt, Netanyahu and Abbas will likely see each other, as well as President Obama, again on the sidelines of the upcoming U.N. General Assembly session in the third week of September.

The talks will face their first tough test shortly after the U.N. gathering, when an Israeli freeze on settlement activity in the West Bank is due to expire. The Palestinians have threatened to walk out of the talks if the freeze is not extended. The Israelis have said the freeze will be allowed to expire.

Michael Oren, Israel’s ambassador to the United States, said negotiators were “very intensely” discussing the matter but urged the Palestinians not to use it as a way of scuttling the talks.

“The Palestinians shouldn’t cherry pick one issue and make it a condition,” he told reporters in a conference call. He said Israel was willing to discuss settlements in their entirety as “a core issue” in the talks.