"We have started studying the proposals immediately when it was handed to us," Asefi told reporters in his weekly press conference." Some points of the package are acceptable, some have ambiguities, and some points need to be strengthened, some should be eliminated."

He said that there was no time limit for Iran to respond, adding that Iran "is not trying to buy time."

"We must study the package, the time is not a problem if necessary, and we will also bring forward our proposals when we respond to them," said the spokesman.

U.S. President George W. Bush said Friday that Iran would have just weeks to declare accepting the six-nation package, or face possible sanctions.

Iranian Foreign Minister Manouchehr Mottaki said Saturday that Iran was studying the proposal and may make its own package in response.

"We hope the Europeans could carefully study Iran's proposals, which may appear in the form of amendments or a totally new package," he said.

European Union foreign policy chief Javier Solana on Tuesday presented a package of both incentives and penalties to Iran to persuade Tehran to suspend uranium enrichment, which was agreed on by the five permanent members of the UN Security Council plus Germany in Vienna on June 1.

Iran's top nuclear negotiator Ali Larijani has expressed cautious optimism over the new package after his meeting with Solana, saying "there were positive steps but also ambiguities."

However, head of Iran's powerful Guardian Council Ayatollah Ahmad Jannati said on Friday that the Islamic republic would not compromise on its nuclear right.

"The package offered is only good for them, not for us," said Jannati, adding that Iran has to maintain uranium enrichment and the west will have no choice but to accept it.

The United States has accused Iran of developing nuclear weapons under a civilian front, a charge categorically denied by Tehran.