Iran's Foreign Minister Manouchehr Mottaki on Thursday rejected calls from the six major powers to give a speedy answer to the incentive package aimed at ending the current crisis over Iran's nuclear programme.

Mottaki told reporters at UN headquarters in New York that Iran is seriously and carefully reviewing the proposed package, stressing that "a response will be in August."

Iran's response will be clear and substantive, he said, adding that the proposed package contains questions and ambiguities which must be cleared.

Mottaki said Javier Solana, the European Union High Representative for Common Foreign and Security Policy, may be able to answer some of Tehran's questions in technical talks expected to be held early next month.

However, "questions and ambiguities on the Iranian side are pending. Therefore, we welcome the discussions and negotiations for clarification of those ambiguities," he argued.