Russian Foreign Minister Sergey Lavrov, right, and U.S. Secretary of State Hillary Rodham Clinton seen during a news conference after their talks in Moscow, Russia, Tuesday, Oct. 13, 2009. Clinton is meeting with Russian leaders on Tuesday to urge their support in pressuring Iran to prove its nuclear program is peaceful. (AP Photo/Ivan Sekretarev, Pool)AP – Russia publicly pushed back Tuesday against U.S. efforts to threaten tough new sanctions if Iran fails to prove its nuclear program is peaceful, dealing an apparent setback to President Barack Obama’s hopes for Moscow’s backing for fresh penalties against Tehran.