WASHINGTON — A bipartisan slate of 44 US Senators urged US President Barack Obama to reconsider talks with Iran unless it agrees to immediate steps to curb its enrichment activity.“Steps it must take immediately are shutting down of the Fordow facility, freezing enrichment above 5 percent, and shipping all uranium enriched above 5 percent out of the country,” said the letter sent Friday to Obama and initiated by Sens. Robert Menendez (D-N.J.) and Roy Blunt (R-Mo.).“On the other hand, if the sessions in Moscow produce no substantive agreement, we urge you to reevaluate the utility of further talks at this time and instead focus on significantly increasing the pressure on the Iranian government through sanctions and making clear that a credible military option exist,” said the letter. “As you have rightly noted, ‘the window for diplomacy is closing.’ Iran’s leaders must realize that you mean precisely that.”Prime Minister Binyamin Netanyahu has derided the talks until now saying that Iran is exploiting them to buy time.The semi-official Iranian Fars news agency described an Iranian official as anticipating “an opportunity to reach agreement” in Moscow.Mohammed Ali Hosseini, Iran’s ambassador to Italy, said in a Thursday news conference that “practical steps” by the six major powers conducting the negotiations would show “potential in bringing about noticeable achievements for either side.”Fars quoted Hosseini as saying Iran would seek international recognition of its right to enrich uranium according to the guidelines of the Nuclear Non-Proliferation Treaty.In fact, the major powers have for years recognized Iran’s right to NPT standards of verifiable civilian nuclear use. The objection is to Iran’s failure to allow the international community to verify such use.In a separate story, Fars quoted Iranian defense officials as saying that they were preparing to produce a nuclear-powered submarine, the Wall Street Journal reported.The Iranians see such a submarine as “peaceful” use of nuclear power, although it would be powered by weapons-grade uranium.The Fordow facility is a reinforced enrichment plant revealed in 2009 by western powers based on information from their intelligence agencies.“Were Iran to agree to and verifiably implement these steps, this would demonstrate a level of commitment by Iran to the process and could justify continued discussions beyond the meeting in Moscow,” the letter said, referring to a third round of talks scheduled for Moscow on Monday.