Salehi, the representative to the International Atomic Energy Agency (IAEA), hinted Iran would have to sign an additional protocol to the nuclear Non-Proliferation Treaty (NPT) despite its objections.
"In the near future, IAEA legal experts will travel to Iran" to continue discussions on the ambiguities of the additional protocol, Salehi said in an interview on Iranian state television.
The additional protocol allows IAEA inspectors to make unscheduled visits to all the country's nuclear installations.
"So far, on the direct orders of President (Mohammad) Khatami and to show good faith and transparency, we have cooperated beyond the accords and allowed the taking of samples and inspections of non-nuclear sites," he said.
Salehi said that in future Iran would go no further than its commitments, "while completing what has been embarked upon."
"The additional protocol is not a good protocol and amounts to interference in the affairs of states," he said.
"But, in any case, the countries which have signed the NPT must sooner or later sign up because they (the IAEA and major powers) have planned things that way," he said.
"It's a bitter reality," he concluded.
Earlier in the day his deputy foreign minister Mohsen Aminzadeh, a close ally of Khatami, spoke in favour of signing the additional protocol.
"If we wanted to build a nuclear bomb, then transparency wouldn't be in our interests, but if we don't want to build a nuclear bomb, which is the case, then signing the protocol and preserving our civil nuclear capacity is in our interests," said Aminzadeh.
"If the United States succeeds in creating a unified opinio against us, then our country will face major difficulties and crises."
An IAEA resolution, passed on September 12 after strong US lobbying, demands Iran answer all the agency's questions on its uranium enrichment activities, grant unrestricted access to UN inspectors and a detailed list of its nuclear-related imports.
Iran fiercely denies it is seeking to acquire nuclear weapons, but its failure to comply could lead to Tehran being declared in non-compliance with the NPT, with the matter being passed to the UN Security Council.