Libya's Moammar Gaddafi said Thursday, in a rare appearance before a US audience, that he evolved from a firebrand revolutionary into a seasoned ruler over four decades in power, contributing to his decision six years ago to dismantle his country's weapons of mass destruction. Gaddafi, one of the world's most enigmatic leaders, struck an almost professorial tone, in contrast to his rambling, antics-filled speech to the UN General Assembly the day before. Clad in a black suit and a transparent black robe, he fielded questions for an hour Thursday at the Council on Foreign Relations, a prestigious think tank. The Libyan leader's first ever visit to the US has drawn curiosity as well as condemnation and derision after Wednesday's theatrical appearance at the General Assembly in which he denounced the UN Security Council a "terror council" - even though Libya is a member. A descendant of Bedouin tribesmen, Gaddafi also caused an uproar over his insistence on pitching a tent, rather than checking into a New York City hotel. The Libyan government erected the tent on land it rented on the estate of real estate mogul Donald Trump in the New York City suburb of Bedford. A town official said Trump had no idea Gaddafi might use the property. On Thursday, Gaddafi spoke on a wide range of issues, but was evasive when pressed about his country's role in the 1988 bombing of Pan Am flight 103 over the Scottish down of Lockerbie. Libyan agents have been suspected in the blast that killed 270 people, most of them Americans. In 2003, Libya acknowledged responsibility for the bombing and agreed to pay up to $10 million to the relatives of each of the victims. However, Gaddafi said Thursday that Libya has not accepted culpability, and only took responsibility for the actions of its citizens. "We never acknowledged any guilt ... and Libya was never indicted in any court as responsible," he said in Arabic. His remarks translated into English. Earlier this year, Libya drew new condemnation for giving a hero's welcome to a Libyan who had been convicted in the Lockerbie bombing and was released by Scotland on humanitarian grounds. Under Gaddafi, Libya had long been a pariah state, sponsoring terrorist groups and trying to undermine pro-Western governments in Africa. The nation gradually emerged from its isolation in recent years. In the aftermath of the Sept. 11, 2001, attacks on the United States, Gaddafi renounced terrorism and dismantled Libya's secret nuclear program. Asked about his motives, Gaddafi said he has undergone a transformation. In the years when Libya still pursued weapons of mass destruction, "we were young people, we were revolutionary, very excited and we were part of the times," he said, adding that "after decades in government we gained experience." Gaddafi said he also calculated the cost and decided the weapons program was becoming too expensive for Libya. The Libyan leader said he would not want Iran to have nuclear weapons. He brushed aside questions about human rights violations in his country, claiming that Libya no longer had a government that could oppress anyone and had moved to a more advanced stage - rule by the masses. "Unless you have deeply studied the theory of the world and the Green Book, I won't be able to shed light on an issue you really don't know much about," Gaddafi admonished the woman who had posed the question. The Green Book is Gaddafi's political manifesto and required reading in Libya.