WASHINGTON (AP) ― President Barack Obama delivered his most explicit threat yet that the United States will attack Iran if that is what it takes to prevent the Islamic republic from developing a nuclear bomb. At the same time, he warned Israelis they would only make a bad situation worse if they moved pre-emptively against Iranian nuclear facilities.

The double-barreled warning, in an interview published Friday, came before Obama’s high-stakes meeting with Israeli Prime Minister Benjamin Netanyahu on Monday and a speech Sunday to the American-Israel Public Affairs Committee, a powerful pro-Israeli lobby. Obama said an Israeli strike would stir sympathy for Iran in a region where it has few allies. But he made clearer than before that Iran could face attack from the United States.

“I think both the Iranian and the Israeli governments recognize that when the United States says it is unacceptable for Iran to have a nuclear weapon, we mean what we say,” Obama told The Atlantic magazine. “I don’t bluff.’’

He said Iran and Israel both understand that “a military component’’ is among a mix of many options for dealing with Iran, along with sanctions and diplomacy, making plain a threat to attack that had previously been more subtly implied.

The warning reveals how the threat that Iran could pose to Israel has eclipsed every other issue in the close but often contentious U.S. relationship with Israel, and raised the political stakes for Obama. Iran’s disputed nuclear ambitions dwarf the unfinished business of peace with the Palestinians and Obama’s sometimes testy relationship with Netanyahu.

The White House dispute with Israel is about the risks versus the benefits of a military strike in the near term, not whether one is ever appropriate. The issue is infused with domestic politics in both the United States and Israel, and Obama is at pains to show American Jewish voters that he is not being harder on Israel than on Iran.

“Every single commitment I have made to the state of Israel and its security, I have kept,’’ he said in the magazine interview. “Why is it that despite me never failing to support Israel on every single problem that they’ve had over the last three years, that there are still questions about that?”

Obama then suggested an election-year answer to his own question, accusing Republicans of trying to fan the doubts and slam a wedge “between Barack Obama and a Jewish-American vote that has historically been very supportive of his candidacy.”

He firmly rejected the notion that the United States might settle for a strategy of letting the Iranians build a nuclear weapon but deterring them from using one.

“You’re talking about the most volatile region in the world,’’ he said. “It will not be tolerable to a number of states in that region for Iran to have a nuclear weapon and them not to have a nuclear weapon. Iran is known to sponsor terrorist organizations, so the threat of proliferation becomes that much more severe. “

Israel has been publicly debating whether to launch air strikes on Iran’s known nuclear facilities in the next several months, before Israel judges that Iran’s program would be too far along to stop. The Obama administration argues that the time for a strike is further away, and that there remains enough time to persuade Iran’s leaders to back down. Iran insists its nuclear program is for peaceful purposes.

Israel wants U.S. backing for any military action against Iran but has signaled it would go it alone if need be. Israeli officials have said they have made no decision yet, but the Obama-Netanyahu meeting comes amid a growing sense in Israel and in Washington that a strike is likely.

Israeli officials appear unmoved by the U.S. arguments, and Obama is unlikely to talk Netanyahu out of launching a strike if the Israeli leader decides not to wait. Both governments maneuvered Friday to set the terms for their discussion.

Netanyahu warned the world Friday not to fall into the “trap” of renewed nuclear talks. Speaking in Canada, the hawkish Israeli leader said he not would set down “red lines” for Israeli or U.S. action on Iran ― a reference to reports in Israel that the country intended to press the United States to set such demands.

Until now, Obama has said a nuclear Iran is unacceptable but has not spelled out just what the U.S. would do or when. White House press secretary Jay Carney told reporters Friday that Obama does not intend to tip his hand to Iran about what lines it cannot cross because doing so would not be in U.S. interests.

Three delegations of senior U.S. national security officials made the case against an Israeli strike in visits to that country over the past month. They argued that launching a strike before the last possible moment, and without international support, would do more harm than good.

It could actually make Israel less safe by angering neighbors that do not like either Israel or Iran but would be forced to side with Iran in the event it were attacked, the U.S. has argued. In that sense, an attack coming from Israel could be even more polarizing in the region than one launched by the United States.

An Israeli strike also would be unlikely to eradicate the Iranian nuclear program, and would at best set it back a few years, the U.S. argument goes. In the end, the Iranian program could grow back stronger.

“At a time when there is not a lot of sympathy for Iran and its only real ally (Syria) is on the ropes, do we want a distraction in which suddenly Iran can portray itself as a victim?” Obama asked in the interview.

Israel takes little comfort in the U.S. assessment, reiterated Tuesday by Secretary of State Hillary Rodham Clinton, that Tehran has not decided whether to build a nuclear bomb.

Israel has refused to guarantee any notice to the U.S. ahead of time, a U.S. intelligence source told The Associated Press. The official spoke on condition of anonymity because much of the planning for Iran is classified. A pre-emptive Israeli strike probably would be similar to Israel’s 1981 strike on an Iraqi weapons site that Israeli officials cite as a success.

Iran’s nuclear ambitions pose a “grave threat to the peace and security of the world,” Netanyahu said, and other nations cannot stand by and allow it to happen. In the past he has likened the growing Iranian nuclear threat to the risk that Nazi Germany represented before the Holocaust.

“As for Israel, like any sovereign country, we reserve the right to defend ourselves against a country, against a country that calls and works for our destruction,” Netanyahu said Friday.

The meeting and Obama’s address to the lobby also will revisit what the U.S. sees as lackluster Israeli efforts toward peace with the Palestinians. It is a sore subject, despite Obama’s strong defense of Israeli actions before the United Nations and in other venues. Before his AIPAC speech last year, Obama outlined U.S. terms for resuming Palestinian peace talks that infuriated Netanyahu and many Israel supporters in the United States.

Netanyahu speaks to the group’s annual conference Monday evening.

The group’s influence and the importance of Jewish voters in American politics have made its glossy Washington conference a must-do for both American and Israeli politicians. Republican presidential candidates Mitt Romney, Newt Gingrich and Rick Santorum also will address the group this year