TEHRAN, June 6 (Xinhua) -- Iran said on Tuesday that a new proposal agreed by six world powers over its disputed nuclear issue contained both "positive" elements and some "ambiguities."

    The proposal drafted by the European Union (EU) was formally presented to Iran on Tuesday by EU foreign policy chief Javier Solana during a meeting with Iran's top nuclear negotiator Ali Larijani held in the building of the Supreme National Security Council in central Tehran.

    "We had more than two hours of talks and the talks were good. We will study these proposals and then give a formal response," Larijani told reporters after the meeting.

    "We can see there are some positive steps in the new proposal, but it also contains some ambiguities," said Larijani, without indicating what parts of the proposals are "ambiguous." "We welcome the European Union to resolve the issue through dialogue and the two sides should have more negotiations again after our careful study of the proposals," added the top nuclear negotiator.

    Meanwhile, Solana held a separate meeting with Iranian Foreign Minister Manouchehr Mottaki on Tuesday.

    After the talks, Mottaki was quoted by the official IRNA newsagency as saying that Iran would "brief friends of its views on Europe's latest proposal to resolve the nuclear issue after careful studies."

    Solana, on his part, termed his one-hour discussion with Mottaki as "good" and praised the current atmosphere of talks, adding "Now that the proposal is on the table, I hope we can receive a positive response which can satisfy both sides."

    Solana arrived in Tehran late on Monday with a new package agreed by the five permanent members of the United Nations Security Council-- the United States, Britain, France, Russia and China-- plus Germany last Thursday.

    The new six-nation package contains economic and political incentives, including talks with the United States, the West's help to build nuclear reactors for Iran, a guaranteed supply of nuclear fuel and permission for Iran to buy aircraft and spare parts if Tehran suspends uranium enrichment.

    The package also includes an implicit threat of UN sanctions if Iran doesn't comply.

    Details of the proposals have not been made public yet. Upon his arrival at the Iranian airport on Monday, Solana told reporters that the five permanent members of the Security Council plus Germany wanted to start a fresh relationship with Iran on the basis of mutual respect and trust.

    "The new proposal could let us be engaged in negotiations based on trust, confidence and respect," said Solana.

    However, Iran has repeatedly claimed that it would never halt uranium enrichment activities under pressure or threat.

    Last weekend, Iranian President Mahmoud Ahmadinejad reasserted during a telephone conversation with United Nations Secretary General Kofi Annan that Iran was ready to hold talks on its nuclear program and that Tehran preferred negotiations to be held democratically without any precondition or any threat.

    Meanwhile, Iran's Supreme Leader Ayatollah Ali Khamenei asserted on Sunday that Tehran must not give up its "scientific goals" in the face of "threats and bribes", warning that if the United States made a "wrong step" over Iran, oil flow in the region would be affected.

    The U.S., which severed diplomatic relations with Tehran in 1980, claims that Iran is using its civilian nuclear program as a cover to produce nuclear weapons, a charge Tehran has repeatedly denied.

    Iran says that its nuclear program is merely to generate electricity, not bombs and that Iran will not give up its legal right to peaceful nuclear technology under the nuclear Non-Proliferation Treaty, to which Tehran is a signatory. Enditem