WASHINGTON - An international naval blockade of Iranian oil exports should be considered before any resort to air strikes against the country's disputed nuclear program, the chairman of the US Senate Armed Services Committee said on Friday."That's, I think, one option that needs to be considered" to boost pressure on Iran to curb its nuclear program in line with UN Security Council resolutions, Democratic Senator Carl Levin said in an interview taped for C-SPAN's "Newsmakers" program. He said any such blockade should be preceded by lining up alternative oil supplies to avoid a price spike on world crude markets. Iran is OPEC's second-largest oil producer and the world's third-largest petroleum exporter.Levin was responding to a question about possible ways of increasing pressure short of combat, including imposition of a "no-fly zone" over Iran.Such moves "could be very effective," he said. "I think (these are) options that whoever is willing to participate should explore, including Israel and including the United States."Iran is widely suspected of enriching uranium, and other activities, as a prelude to building nuclear weapons. Tehran says the program is aimed at producing civilian nuclear power.The international response to Iran's nuclear program has evolved into a widespread consensus for substantial sanctions and other pressure, paired with incentives and diplomacy, to head off the possible development of nuclear arms.Levin voiced optimism that increasingly strict sanctions, including an oil purchase embargo by the European Union to take full effect by July 1, might force Iran to relent."Not because it doesn't want a nuke - I think it does - but because the price that it's going to have to pay" in terms of isolation would be too high, said Levin, whose committee has an oversight role for the US Defense Department.Levin said US President Barack Obama should seek congressional authorization before any US resort to military action against Iran. But he noted that presidents from both parties had maintained they were not bound to do so as commander in chief of US armed forces.A senior Obama administration official, asked about Levin's remarks, said, "Our focus remains on a diplomatic solution, as we believe diplomacy coupled with strong pressure can achieve the long-term solution we seek."Levin said he would not be surprised if Israel took military action within "months.""I would say that a strike is likely" if Iran continues to refuse to curb its nuclear program, he added. He said US-supported Israeli missile defense programs had undercut Iran's ability to retaliate against Israel for any strike.Asked why Israel alone should be allowed to have nuclear arms in the region, Levin cited the Holocaust, the genocide of about 6 million European Jews during World War Two by Nazi Germany, and what he called similar threats throughout history.In addition, he said, Israel still faced a threat of being wiped out by some of its neighbors, "so it's a deterrent against that kind of a threat."