US Senator Joe Lieberman defended himself Wednesday from criticism that he is pressing for war with Iran, telling The Jerusalem Post he merely wants to strengthen US diplomacy with a credible threat of force. After Lieberman told CBS's Face the Nation Sunday that the US had to be prepared to use "aggressive military action" against Iran because of its behavior in Iraq, he faced a barrage of criticism that he was warmongering. Zbigniew Brzezinski, former president Jimmy Carter's national security adviser, said political leaders such as Lieberman, "echoed by some powerful lobbyists, are actually at the moment pushing the military option." Perceiving the comments as referring to the pro-Israel lobby, the Anti-Defamation League slammed Brzezinski for giving weight to conspiracy theories about Jews hawkishly controlling government policy on Iran. Lieberman responded to the criticism by emphasizing that he had spoken on Sunday, "as an American senator," and had been expressing his concern about Iranian actions against US soldiers in Iraq. "They have started military action against us, not vice versa," Lieberman told the Post. "If we don't try diplomacy and then back it with credible threat of force, shame on us, we're going to pay for it later." He was speaking after an appearance at the Orthodox Union Leadership Mission to Washington's Senate luncheon Wednesday afternoon. At the lunch, Lieberman told the crowd his words helped encourage debate on how to handle the threat posed by Iran. "This is a very serious situation," he said. "We've learned from history - from Hitler, from bin Laden - that what Hitler said in the '30s that he was going to do, he actually tried to do, that what bin Laden said he was going to do, he actually tried to do." Lieberman said Iranian President Mahmoud Ahmadinejad's threats toward Israel and the United States also had to be taken seriously.