Tehran, Iran ? Iran and the United States on Sunday heralded a crucial week of decision-making at the International Atomic Energy Agency by exchanging thinly veiled threats about the consequences of a vote to send the issue of Iran’s nuclear program to the U.N. Security Council.

Iran’s chief negotiator renewed a threat to interrupt petroleum exports if the IAEA board of governors followed through on its vote last month to report Iran to the Security Council pending a last stab at a diplomatic solution. Iran is the second-largest producer in the Organization of the Petroleum Exporting Countries.

“If we are referred to the Security Council, problems might occur for others as well as us,” Ali Larijani said at a news conference. “We would not like to use our oil as a weapon. We would not like to make other countries suffer.”

The U.S. ambassador to the United Nations, John Bolton, in turn warned of “painful consequences” if Iran made good on a separate threat, also repeated Sunday in Tehran, to answer a punitive vote by moving rapidly toward large-scale uranium enrichment. Enriching uranium can produce fuel for civilian power reactors, which is all Iran says its nuclear program is intended for. The same process, if taken further, can produce fuel for nuclear warheads, which the Bush administration and other skeptics assert is Iran’s ultimate goal.

Bolton was speaking at the convention of a pro-Israel lobby, the American Israel Public Affairs Committee.

President Bush has repeatedly said the possibility of military strikes remains “on the table” even as Washington endorsed an intense international diplomatic effort.

The IAEA meeting has loomed as a showdown since Feb. 4, when the agency’s governing panel voted 27 to 3 to discipline Iran for resuming nuclear research, some two years after voluntarily suspending nuclear research amid concerns that the program, because it had been largely secret, was not purely civilian. The Security Council has the power to impose economic or other sanctions on Iran, though diplomats say the council would likely choose measures that gradually increased pressure on Tehran.

The IAEA board, which convenes in Vienna, is not expected to take up Iran’s file until Tuesday, and diplomats said a final vote probably would not come until late in the week. That leaves several days for last-ditch negotiations, and on Sunday Iranian officials indicated the talks might bear fruit.

Attention remained focused on a Russian offer to enrich uranium to low-grade fuel on its soil, ship the fuel to reactors in Iran, then bring the spent fuel back to Russia so there was no possibility any might be diverted for military use. But Larijani said the vote in Vienna could imperil that proposal.

“If Iran is referred to the Security Council, Iran will start enrichment, so there’s no need to have another country do enrichment for us,” he said.

A key sticking point is Iran’s insistence that it be allowed to continue at least small-scale enrichment within its borders, in the name of research. Larijani said Sunday that Iran was willing to suspend large-scale enrichment as part of a “package” that he declined to detail.

He repeatedly warned, however, that Iran would not tolerate its program being sent to the Security Council, and being subjected to forced inspections as neighboring Iraq was through the 1990s.

“But we’re not willing to be like Iraq, to let them come into the country whenever they want and look in any corner they want,” he said.