Iranian officials are reacting cautiously to a package of incentives proposed by six world powers in a bid to convince Tehran to end its nuclear enrichment program.  Iranian leaders are promising to study the plan.

Javier Solana (l) meeting in Tehran with Iran's Foreign Minister Manouchehr Mottaki

European Union foreign policy chief Javier Solana presented the plan to Iranian officials, whose low-key response marked a sharp change from the heated rhetoric of the last several weeks.

The Iranian foreign minister said Tehran will study the incentive package carefully.

Iran's top nuclear negotiator, Ali Larijani, said the package has both "positive steps" and "ambiguities."  He did not elaborate on what those ambiguities were.

Larijani welcomed Europe's effort to solve the nuclear issue through dialogue, calling it a positive step.  Then he said, "We hope we can hold talks after we have studied the proposals, so we can reach a rational solution to the issue."

The plan is designed to persuade Iran to give up its nuclear enrichment program.  It includes specific incentives, as well as penalties if Iran does not comply.  The plan emerged after weeks of negotiating by the United States, Britain, France, Russia, China and Germany.

Javier Solana said the package of incentives represents the "strong consensus" of the six countries that proposed it.

"I think the atmosphere was very good," said Mr. Solana.  "We are gong to try to continue.  The government and the leaders do have a proposal sent by a group of countries, European countries... and I hope very much that we will have soon an answer, and we would like very much to continue working and seeing we can achieve a good agreement that would be beneficial for everybody."

While the six world powers were negotiating the contents of the package over the last several weeks, Iranian officials have repeatedly rejected the idea of abandoning nuclear fuel enrichment, which they consider their right.

Iranian President Mahmoud Ahmedinejad compared it to offering a child walnuts and chocolate in exchange for gold.

The entire proposal has not yet been made public, but some of the details have been reported in the Western press.  The New York Times newspaper says the United States is willing to partly lift its bilateral trade sanctions, allowing Iran to buy American airplane parts and agricultural technology.

The Times says Iran could purchase airplane parts from the American company Boeing, as well as aircraft and spare parts from the European firm Airbus.  The newspaper calls that offer "a huge step" for the United States.

Iran has a troubled air safety record.  The government frequently blames air crashes on the U.S. embargo, which prevents Tehran from buying spare parts for its aging fleet.  Most of Iran's civilian and military aircraft are Boeings bought before the 1979 Iranian revolution.

Another widely reported part of the proposal involves European help in building a light-water nuclear reactor that Iran could use to produce nuclear energy, which is what it says it wants from its nuclear program.

If Iran refuses to abandon uranium enrichment, the possible penalties written into the plan are reported to include a travel ban on some Iranian officials and religious leaders, and the freezing of foreign-held financial assets.