But the United States has vowed to keep up pressure on Iran at the International Atomic Energy Agency's (IAEA) board of governors meeting to answer claims that it is secretly developing nuclear weapons.
In Tehran, Iran's top national security official declared Sunday that the Islamic republic would seek to have the IAEA close its file and list of concerns on the country's nuclear program.
"We must arrive at a stage where the (IAEA) board of governors ... take this off the agenda," Hassan Rowhani, the head of the Supreme National Security Council, was quoted as saying by state media.
"The international community has to accept Iran in the world nuclear club" as a peaceful user of atomic energy, he said.
But US Undersecretary of State John Bolton said in Lisbon last week: "We are absolutely determined not to reduce the pressure on Iran."
He said however that Washington would not seek a referral to the United Nations Security Council that could lead to sanctions over Iran's continuing failure to declare possibly weapons-related activities.
But the bottom line is that the United States does not have the backing at the IAEA's 35-nation board of governors to take the matter to the Council.
The meeting that begins Monday could last until Friday, an IAEA spokeswoman said.
Britain, France and Germany had in October struck a deal with Iran to cooperate with the IAEA, and are still stressing the path of "constructive engagement", a Western diplomat said.
He said the United States has already drafted a resolution against Iran for hiding sensitive parts of its nuclear program as it wants to find a "way of keeping the pressure on" Tehran to fully dislose its activities.
But he said the Europeans would watch carefully the wording of the resolution, in order not to go too far in condemning the Iranians.
IAEA chief Mohamed ElBaradei has said progress is being made with Iran as well as in Libya, which promised in December to do away with its programs to develop weapons of mass destruction.
The United States, Britain and Libya have reached an agreement for Tripoli to accept the IAEA declaring it to the Security Council for past non-compliance with the nuclear Non-Proliferation Treaty (NPT) while praising it for its current cooperation in eliminating weapons development programs, the Western diplomat said.
He said Libya, unlike Iran, is "almost done in revealing its nuclear program" and the non-compliance declaration would merely be a "pro-forma" way of closing this chapter with no threat of sanctions against the north African state.
The diplomat said this was also meant as a message to Iran that the agency will not back off until verification is complete, with cooperation eventually being rewarded as in Libya's case, while sanctions remain possible as a punishment for non-cooperation.
The IAEA said in a report last month that Iran had failed to declare possibly weapons-related atomic activities despite promising full disclosure and warned Tehran to make sure this didn't happen again.
Iran had not told the IAEA it had designs for sophisticated "P-2" centrifuges for enriching uranium nor that it had produced polonium-210, an element which could be used as a "neutron initiator (to start the chain reaction) in some designs of nuclear weapons," the report said.
This was despite Iran's claim last October that it had given the IAEA a full picture of its nuclear program.
Meanwhile, ElBaradei will be warning on Monday that non-proliferation safeguards must be strengthened and is expected to get backing from the board for the IAEA to "continue investigation into the Pakistani-run nuclear black market" that supplied programs in North Korea, Iran and Libya, the diplomat said.