WASHINGTON — Amid increasing suggestions that Israel might attack Iran's nuclear facilities, Defense Secretary Robert M. Gates warned this week that such a strike would have dangerous consequences, and asserted that Tehran's acquisition of a bomb can be prevented only if "Iranians themselves decide it's too costly."
Using his strongest language on the subject to date, Gates told a group of Marine Corps students that a strike would probably delay Tehran's nuclear program from one to three years. A strike, however, would unify Iran, "cement their determination to have a nuclear program, and also build into the whole country an undying hatred of whoever hits them," he said.
Israeli officials fear that the Islamic Republic may gain the know-how to build a bomb as early as this year. Several of them have warned that Israel could strike first to eliminate what it considers an existential threat.
Iran responded this week to the Israeli declarations, asking the United Nations to intervene to stop the threats.
Mohammad Khazaee, Iran's ambassador to the United Nations, sent a letter Tuesday to the president of the U.N. Security Council denouncing "unlawful and insolent" threats of an attack. He said the threats violated international law and the U.N. Charter, and urged the organization to respond.
Israeli officials would probably seek the cooperation and approval of their American allies before carrying out any such strike, experts say.
One reason is that Israelis may want U.S. clearance to fly over Iraq, and possibly help with aircraft refueling or other aspects of the operation. In addition, a strike could set off retaliatory Iranian attacks on U.S. forces in Iraq and Afghanistan, straining relations between the two allies.
Though the Obama administration has not ruled out the use of military force, several officials have indicated strong opposition to using it. Last week, Vice President Joe Biden said Israel's new conservative prime minister, Benjamin Netanyahu, would be "ill advised" to launch a strike.
Shimon Peres, Israel's president, said in an interview with Israel's Kol Hai Radio on Sunday that Israel would attack if Iranian President Mahmoud Ahmadinejad didn't drop his plans for the nuclear program.
"We'll strike him," Peres said in the interview.
Netanyahu has also hinted at the possibility of an Israeli attack, describing the Iranian program as an "existential threat."
Obama administration officials are exploring whether they can convince Tehran through negotiations to give up its nuclear ambitions. Officials have said they are ready to try to intensify economic and political sanctions on Iran if diplomacy doesn't work.
Gates told students at Marine Corps University in Quantico, Va., that while President Obama "needs the full range of options," in his view "we need to look at every way we can to increase the cost of that program to them, whether it's through economic sanctions or other things."
The Defense secretary said other nations need to put more emphasis on arguments that a bomb would diminish rather than improve Iran's security, "particularly if it launches an arms race in the Middle East."
Gates' comments were delivered on Monday and first reported by the Army Times newspaper. A Defense official confirmed their accuracy.
The comments by Gates and Biden suggest that in their private conversations, U.S. officials are discouraging such a course, even though officials say they would never deny Israel's right to act in self-defense.
Staff writer Julian E. Barnes in Washington contributed to this report.