Nearly half the U.S. Senate told President Barack Obama on Friday that unless Iran gives three specific concessions at the talks in Moscow with the group of six world powers, he should abandon the ongoing negotiations over the country´s nuclear program, The Cable reported.

"It is past time for the Iranians to take the concrete steps that would reassure the world that their nuclear program is, as they claim, exclusively peaceful," wrote 44 senators in a bipartisan letter organized by Sens. Robert Menendez (D-NJ) and Roy Blunt (R- MO). "Absent these steps, we must conclude that Tehran is using the talks as a cover to buy time as it continues to advance toward nuclear weapons capability. We know that you share our conviction that allowing Iran to gain this capability is unacceptable."

The senators wrote that the "absolute minimum" Iran must do immediately to justify further talks is to shut down the Fordo uranium enrichment facility near Qom, freeze all uranium enrichment above 5 percent, and ship all uranium enriched above 5 percent out of the country.

"We understand that this was the very proposal that the P5+1 advanced during the Baghdad meeting," the senators wrote, referring to the permanent five members of the U.N. Security Council plus Germany. "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."

Few expect the Moscow meeting to yield tangible results or unilateral actions by Iran.

The senators are urging the president not to ease or delay the embargo, writing that only when the Iranian government believes the sanctions are to be "unremitting and crippling" will a diplomatic breakthrough will be possible, The Cable reported.

"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 exists," they wrote. "As you have rightly noted, ‘the window for diplomacy is closing.´ Iran´s leaders must realize that you mean precisely that."

The letter is also signed by Charles Schumer (D-NY), Susan Collins (R- ME), Benjamin Cardin (D-MD), Johnny Isakson (R-GA), Richard Blumenthal (D-CT), Kelly Ayotte (R-NH), Joseph Lieberman (I-CT), James Risch (R-ID), Ron Wyden (D-OR), David Vitter (R-LA), Frank Lautenberg (D-NJ), Jerry Moran (R-KS), Mark Pryor (D-AR), John Cornyn (R-TX), Robert Casey Jr. (D-PA), John Boozman (R-AR), Kirsten Gillibrand (D-NY), Jeff Sessions (R-AL), Sherrod Brown (D-OH), Scott Brown (R-MA), Debbie Stabenow (D-MI), Mike Crapo (R-ID), Amy Klobuchar (D-MN), John Hoeven (R-ND), Jeff Merkeley (D-OR), Daniel Coats (R-IN), Christopher Coons (D-DE), Lisa Murkowski (R-AK), Ben Nelson (D-NE), Patrick Toomey (R-PA), Michael Bennet (D-CO), Mike Lee (R-UT), Daniel Inouye (D-HI), Rob Portman (R-OH), Barbara Mikulski (D- MD), Dean Heller (R-NV), Jon Tester (D-MT), Kay Hagan (D-NC), Bill Nelson (D-FL), Mark Warner (D-VA), Carl Levin (D-MI), and Mark Begich (D-AK).

"The message of this letter is that Congress´ patience is running out when it comes to meetings that don´t yield results," said a senior Senate aide. "The Iranians have been given every last opportunity to demonstrate their good faith and step back from the brink. Instead, they keep pushing forward with their nuclear program, and we keep asking for yet another round of talks. This is not sustainable." (IsraelNationalNews © 2012 06/17/12)