Iran's supreme leader, Ayatollah Ali Khamenei, said Monday that his country was leading the world's nations in their confrontation against the US, Iranian state television reported. Khamenei's comments came exactly one week before US and Iranian ambassadors are scheduled to meet in Baghdad to discuss the security situation in Iraq, providing one more reason to question whether the upcoming talks will be productive. "In the field of confrontation of nations against the arrogant system of the United States, the Islamic Republic of Iran has turned into a command center for the nations' front," the television quoted Khamenei as saying while meeting a group of students. Iran's leader, who has final say over all state matters, said his country's 1979 Islamic revolution sent shock waves through the international system because it produced a country willing to challenge the US "The Islamic system (of Iran) detonated a powerful bomb in the world of politics, which was thousands-fold stronger than the bomb detonated by the US in Hiroshima," he was quoted as saying. The supreme leader said Iran had shown nations around the world that it was possible to oppose Washington's policies, calling this "bitterer than any conceivable poison for the US" Khamenei is considered a hard-liner, and although he gave his backing on Wednesday to the upcoming talks with the US, he said the meeting would focus on fixing Washington's policies in Iraq, not changing Iran's. Iran has called for US troops to withdraw from Iraq, blaming their presence for the country's bloodshed. Washington accuses Iran of aiding Shiite militants in Iraq, a claim Teheran denies. The two countries are also at loggerheads over Iran's nuclear program. The US and some of its allies accuse Iran of seeking to build nuclear weapons, but Teheran has maintained that its program is peaceful.