Iran formally responded Tuesday to a package of Western incentives aimed at persuading Tehran to suspend uranium enrichment, with officials saying it has offered a “new formula” to resolve the dispute.

Iran’s top nuclear negotiator, Ali Larijani, hand-delivered Iran’s response to the Western package of nuclear incentives to ambassadors from Britain, China, Russia, France, Germany and Switzerland, state-run television said, without disclosing details.

Officials close to the meeting said Iran’s response offered the “new formula” to resolve the dispute over Tehran’s nuclear activities. The officials spoke on condition of anonymity because of the sensitivity of the information.

A top Iranian nuclear official said Tehran’s response will provide “an exceptional opportunity” for a return to the negotiating table for a compromise.

“Iran’s response to the package is a comprehensive reply that can open the way for resumption of talks for a final agreement,” Mohammed Saeedi, deputy head of the Atomic Energy Organization of Iran, said in comments published Tuesday.

Even so, Iran on Monday twice showed its determination to push ahead with its nuclear program, which continues under the possible threat of economic and diplomatic sanctions imposed by the U.N. Security council if it does not halt uranium enrichment by Aug. 31.

It turned away International Atomic Energy Agency inspectors from an underground site meant to shelter its uranium enrichment program from attack and its top leader, Ayatollah Ali Khamenei, declared that Tehran will continue to pursue its nuclear activities.

Iran has rejected the resolution passed by the council last month as “illegal,” saying a compromise can only emerge from talks.

Likewise, Saeedi’s optimistic words Tuesday were tempered by his assessment of the proposed packaged as containing “serious ambiguities” that need to be clarified in talks.

The package does not mention the part of the Nuclear Nonproliferation Treaty that affirms signatories’ right to pursue nuclear technology for peaceful purposes, Saeedi said.

“One ambiguity is the deliberate failure to mention Article 4 of the NPT in the package. Instead, it has repeatedly referred to other parts of the treaty that are mainly deterrent. Why Article 4 has not been mentioned?” Saeedi asked.

Iran promised Sunday to offer a “multifaceted response” to the package of incentives, proposed in June by the five permanent members of the U.N. Security Council plus Germany.

The council’s July 31 resolution came in response to Tehran’s delay in replying to the proposal.

The United States and some of its Western allies accuse Iran of seeking nuclear weapons. Tehran has denied the charges saying its nuclear program is merely aimed at generating electricity, not bombs.

The Islamic republic has repeatedly said it will never give up its right to enrich uranium and produce nuclear fuel, but has indicated it may temporarily suspend large-scale activities to ease tensions.