Ambassadors from six world powers reached agreement in principle on a proposed new package of sanctions against Iran and expect to introduce a resolution to the UN Security Council on Thursday if their governments give a green light, the US ambassador said. Approval by the governments of the United States, China, Russia, Britain, France and Germany would be an important first step. The package would still need to be considered by the 10 non-permanent members of the UN Security Council who are elected for two-year terms and have not been part of the negotiations. Nonetheless, an agreement by the five veto-wielding permanent members of the council and Germany would be a strong signal to the other council members of the unity of the key nations on the UN's most powerful body - and a sign that they want to send a united message to Iran to suspend uranium enrichment. "We have an agreement in principle based on some additional changes that were introduced and presented today by some delegations," acting US Ambassador Alejandro Wolff said Wednesday. "So it's new elements and understandings that need confirmation from capitals. But it is a package approach that, if approved by captials, would be essentially the way forward in a resolution." Russia's UN Ambassador Vitaly Churkin said "by and large it has been agreed." "There are some among us ... who still want to double-check with the capitals on some of the details of this deal," Churkin said. "I assume as they double-check, they will get a positive response from the capitals, and they expect that this is going to be the case, too." In December, the UN Security Council voted unanimously to impose limited sanctions against Iran for its refusal to freeze uranium enrichment. It ordered all countries to stop supplying Iran with materials and technology that could contribute to its nuclear and missile programs and to freeze assets of 10 key Iranian companies and 12 individuals related to those programs. The council said it would consider further nonmilitary sanctions if Iran refused to suspend enrichment. Iran's response was to accelerate its enrichment program. The modest package of new measures agreed to by ambassadors from the six countries includes an embargo on Iranian arms exports and an asset freeze on more individuals and companies associated with Teheran's nuclear and missile programs, council diplomats said. The new resolution would also call on all UN member states to exercise "vigilance and restraint" on arms imports - and on the entry or transit through their territory of Iranians subject to the asset freeze, a council diplomat said. It would also call on governments to make no new commitments "of grants, financial assistance, or loans to the government of Iran," the diplomat said, speaking on condition of anonymity because the text has not been circulated. The United States and the Europeans would certainly favor tougher sanctions, but knew they had to settle for less to ensure that Russia and China, which have close commercial ties with Iran, will not use their veto power to block a resolution. The Western powers have also stressed the importance of maintaining council unity. "It is our hope that the appeal of the Security Council will be constructively responded to by the Iranian side," said Churkin. "Of course, I hope I'm not daydreaming, but there is still time for Teheran to give a positive response, and in that case a vote on this draft resolution would not be necessary." China's UN Ambassador Wang Guangya said the six ambassadors met informally and came up with some small changes to improve the text before agreeing to send it to capitals. Referring to the list of additional individuals and entities that would be subject to sanctions, Wang said, "I'm not happy, but I think one has to reach agreement, so there has to be a package." He said Beijing wants to make sure that sanctions will not apply retroactively to those added to the list - which is several pages long - and that the individuals and companies are involved in Iran's nuclear and missile program. "This is information provided by others," Wang said. "I always remind members that ... many of the intelligence or information can be wrong. So that's why I think we have to be careful with the list." South Africa's UN Ambassador Dumisani Kumalo, the current council president, said Tuesday that several non-permanent members "were very unhappy" at being left out of the negotiations on a new Iran resolution and felt marginalized. The permanent members agreed to hand over a draft of whatever they had late Wednesday afternoon. But France's UN Ambassador Jean-Marc de La Sabliere said "they have been very patient with us and they have accepted that it will be presented tomorrow." Wang said the permanent members "agreed to give elected members sufficient time to study the text." Kumalo said the text will be sent to capitals on Thursday and consultations of the full council will begin next week. "We anticipate that the voting would happen maybe well into next week," he said. Iran insists its enrichment program is peaceful and aimed solely at producing nuclear energy, but the US, European nations and the UN nuclear watchdog are concerned that Iran's goal is to produce nuclear weapons. Kumalo said he spoke to Iran's Ambassador Javad Zarif about Sunday's surprise announcement that President Mahmoud Ahmadinejad wants to fly to New York to put Teheran's case for a nuclear program before the Security Council. He said he still had not received a letter "but I understand the possibility now is that there may be a high-level participation of the government of Iran on the day when the resolution is adopted."