UN Secretary-General Kofi Annan called for key parties to seek a negotiated settlement with Iran over its nuclear program and warned that military intervention would be "unwise and disastrous." Annan issued the warning Tuesday as the Security Council debated a resolution that would impose sanctions on Teheran for refusing to suspend uranium enrichment and as the United States considered sending a second aircraft carrier to the Gulf as a show of force against Iran. After two rounds of closed-doors talks Tuesday, the six key nations trying to negotiate with Iran - Britain, France, Germany, the US, Russia and China _ remain divided on the scope of sanctions. They scheduled another meeting on Wednesday. "Our goal is to get this resolution done this week," said acting US ambassador Alejandro Wolff. But Russia's UN Ambassador Vitaly Churkin said he was more concerned about the content than the timing. Annan addressed concerns about a possible military operation in Iran during his farewell news conference before stepping down as UN chief on Dec. 31, responding to a question about how the Security Council should deal with crises after the Iraq war. The council refused to authorize a war against Saddam Hussein in 2003 and Annan called the UN's failure to stop the conflict "the worst moment" of his 10 years as secretary-general. "You mentioned Iran, which implies that there is concern that there may be another military operation there," Annan told the reporter. "First of all, I don't think we are there yet, or we should go in that direction." "I think it would be rather unwise and disastrous," the secretary-general warned. "I believe that the council, which is discussing the issue, will proceed cautiously and try and do whatever it can to get a negotiated settlement for the sake of the region and for the sake of the world," he said. President George W. Bush's administration has repeatedly declined to rule out the use of force against Iran, though senior officials have also said their first choice is to rely on diplomacy. A senior US defense official said Tuesday the idea of building up U.S. Navy forces has been discussed over some time and one proposal is to send a second aircraft carrier to the region. The official, speaking on condition of anonymity because the idea has not been approved, said it is unclear when a decision will be made. Iran insists its nuclear program is aimed solely at the peaceful production of nuclear energy, but the Americans and Europeans suspect Teheran's ultimate goal is the production of nuclear weapons Iranian President Mahmoud Ahmadinejad reiterated Tuesday that possible Security Council sanctions would not stop Iran from pursuing uranium enrichment, a technology that can be used to produce nuclear fuel for civilian purposes or fuel for a nuclear bomb. Annan expressed concern that because of Iran's nuclear program and the situation in Israel, which is widely believed to possess nuclear weapons, several governments in the Middle East have said recently they are going to explore facilities to produce nuclear energy. "What I'm worried about is we may see competitive development of these devices," Annan said. "And we need to take time _ we need to take real effort to assure that we don't get into that situation in the region." The latest draft resolution being discussed by key Security Council members would order all countries to ban the supply of specified materials and technology that could contribute to Iran's nuclear and missile programs. It would also impose a travel ban and asset freeze on key companies and individuals in the country's nuclear and missile programs named on a UN list. Russia and China remain at odds with the US and key European countries, however, over the travel ban and a list of companies and individuals that should be subject to a freeze of their financial assets. "We still have some difficult problems to resolve," Russia's UN Ambassador Vitaly Churkin said after Tuesday afternoon's meeting. He called the travel ban "an unnecessary irritant," and reiterated that Moscow has still not agreed with the list. China's UN. Ambassador Wang Guangya said there were still differences in a number of areas. "I would say sometimes it looks like a technical difference, sometimes it looks like a political difference," Wang said. Wolff said the US views the travel ban as "a priority." "It's a complicated exercise," he said. The six countries offered Iran a package of economic incentives and political rewards in June if it agreed to consider a long-term moratorium on enrichment and committed itself to a freeze on uranium enrichment before talks on its nuclear program. With Iran refusing to comply with an Aug. 31 council deadline to stop enrichment, Britain and France circulated a draft sanctions resolution in late October.