The Obama administration does not know Israel\'s intentions regarding potential military action against Iran, and the uncertainty is stoking concern in Washington, where the preferred course for now is sanctions and diplomatic pressure. Although Israel remains one of the United States\' closest allies and the two countries\' officials are in regular contact, US officials have a \"sense of opacity\" regarding what might prompt an Israeli military strike on Iranian nuclear sites, and about when such an attack might occur, according to a senior US national security official. Two key US senators acknowledged on Tuesday that there are gaps in US knowledge about Israeli leaders\' thinking and intentions. \"I don\'t think the administration knows what Israel is going to do. I\'m not sure Israel knows what Israel is going to do ... That\'s why they want to keep the other guys guessing. Keep the bad guys guessing,\" said Democratic Senator Carl Levin, chairman of the Senate Armed Services Committee. Senator John McCain, the senior Republican on the committee, echoed Levin\'s view: \"I\'m sure [administration officials] don\'t know what the Israelis are going to do. They didn\'t know when the Israelis hit the reactor in Syria. But the Israelis usually know what we\'re going to do.\" Anti-American sentiment In one way, the ambiguity is an advantage for the United States, because Washington could claim it had no foreknowledge of any Israeli attack, which would almost certainly increase anti-American sentiment among many Muslims in the Middle East. Israeli leaders have not suggested an attack on Iran\'s suspected nuclear weapons sites is imminent. But neither have they - or US President Barack Obama, for that matter - ruled it out. Israel, widely believed to have the only nuclear arsenal in the Middle East, says a nuclear-armed Iran would threaten its existence. Iran says its nuclear program is entirely peaceful and denies Western accusations it is seeking an atomic bomb. The uncertainty comes amid extraordinarily sharp public warnings in the last few weeks by US Defense Secretary Leon Panetta about the potential \"unintended consequences\" of military action against Iran. Panetta told a forum in Washington last week that an attack on Iran would risk \"an escalation\" that could \"consume the Middle East in confrontation and conflict that we would regret.\" It could disrupt the fragile economies of the United States and Europe, spark a popular backlash in Iran bolstering its rulers and put U.S. forces in the region in the firing line, he said.