US Undersecretary of State John Bolton said in Lisbon Thursday 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 he said: "We are absolutely determined not to reduce the pressure on Iran."
The bottom line is that the United States does not have the backing at the watchdog International Atomic Energy Agency's (IAEA) 35-nation board of governors to take the matter to the Council when the board begins a regular meeting in Vienna on Monday.
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 reached an agreement in London Tuesday 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.
Iran claims its nuclear program is peaceful and wants the IAEA to end its investigations.
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.
"If the world does not change course, we risk self-destruction," ElBaradei had said in a New York Times article in February that said global smuggling "can deliver systems for producing material usable in (nuclear) weapons."
ElBaradei has urged countries to impose tougher export controls on nuclear material.
He has also said the NPT, which went into effect in 1970, needs updating in order to keep tighter control on possible atomic weapons development.
Experts have said Iran is an example of a country which could be developing the technology to make atomic weapons, even while honoring the NPT. Much sensitive nuclear technology, such as enriching uranium, can have both civilian and military applications.
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.