Iran still has a peaceful way out of the growing confrontation over its nuclear program, the White House said on Wednesday, but a spokesman would not confirm reports that US President Barack Obama wrote to Iranian leaders expressing a readiness to talk.White House spokesman Jay Carney said Iran should engage major powers in discussions about its nuclear work, which the United States and many other countries say is intended to build a nuclear weapon, as European Union foreign policy chief Catherine Ashton outlined in a letter in October.RELATED:Ya'alon: Elections handcuffing Washington on IranBarak: Islamic regime in Iran won’t last forever"If the Iranians are serious about restarting talks, then they need to respond to that letter," Carney told a White House briefing. "That is the channel by which...the restarting of those talks would take place."Carney declined to confirm reports from Tehran that Obama had sent Iranian leaders a new letter about talks, but did not deny a letter had been sent. Direct communications between the US and Iranian governments, which have no diplomatic ties, are rare.Obama rejected criticism from Republican presidential candidates over his foreign policy vis a vis Iran, saying he would take "every step available" in order to stop Iran from developing a nuclear bomb, AFP quoted the president as saying on Wednesday in an interview to Time magazine.Obama said that he could not "guarantee" that Iran would cease its nuclear ambitions by its own accord, saying that the US has not taken "any options off the table in preventing them from getting a nuclear weapon." The US president was responding to criticism by Republican presidential candidates in a Monday debate in South Carolina who questioned his foreign policy. He claimed those lawmakers were seeking to win over the local Republicans by attacking the president's handling of global issues. Obama insisted that the US was in a stronger position than it was when he was elected in 2008, according to AFP.