Key lawmakers, including Democratic presidential candidate Barack Obama, criticized the Bush administration Wednesday for increased US exports to Iran despite tough talk about its nuclear ambitions and meddling in Iraq. The Associated Press reported Tuesday that the value of US exports to Iran has grown significantly during President George W. Bush's years in office - from about $8 million in 2001 to nearly $150 million last year. The exports, made under agricultural, medical and humanitarian exemptions to US trade sanctions, included cigarettes, bull semen, corn, soybeans and medicine, among other goods. "It's that kind of mixed signal that has led to the kind of situation that we're in right now," Obama said Wednesday on ABC television's "Good Morning America." The chairman of the House Foreign Affairs Committee, Howard Berman, remarked on the growth in US trade during comments on the European Union's recent move to toughen financial sanctions on Iran. "It's time for them to take far more significant steps along the lines of cutting off all significant commerce with Iran, as we did years ago - or at least I thought we did. I'm not so sure, after yesterday's Associated Press report that US exports to Iran have increased nearly twenty-fold during the Bush administration years, up to nearly $150 million in 2007," Berman, a Democrat, said at a committee hearing Wednesday. Rep. Dan Burton, a Republican, said the growth in US exports did not make sense to him at a time when the United States was trying to pressure Iran to abandon its nuclear efforts. He said the United States needs to set a strong example for the rest of the world on Iran. "I understand it's the government we're after, and not the people, but nevertheless if the people are upset, they're going to put pressure on the government, and some pressure on the people over there by cutting off trade with them in certain areas that they want would also be very, very beneficial," Burton said. Rep. David Scott, a Democrat, asked Undersecretary of State William Burns to respond to the AP's findings and what he called a "sort of schizophrenic approach" to US trade with Iran. Burns replied that the US government's quarrel is with the government of Iran, not with its people, and that US shipments account for a tiny fraction of Iran's total imports. Burns insisted the administration is "committed fully to using all diplomatic tools" in dealing with Iran, and said the use of force also remains on the table as "a last resort."