The visit by the director general of the International Atomic Energy Agency (IAEA) comes at a time when revelations from Tripoli are helping unravel a nuclear black market from which Libya and North Korea have benefitted.

ElBaradei has been invited by the Libyan government to visit on February 23 and 24 "to review progress", IAEA spokesman Mark Gwozdecky told AFP Monday.

A Western diplomat close to the IAEA said "things have been moving very smoothly" in disarming Libya since it agreed with Britain and the United States on December 19 to dismantle its programs to develop weapons of mass destruction.

The IAEA is the lead agency for verifying nuclear disarmament. ElBaradei visited Libya shortly after the December 19 announcement in order to start the agency's inspections there.

The diplomat said Libyan officials "just wanted to touch base" with ElBaradei prior to an IAEA board of governors meeting in Vienna that begins March 8 and which is to consider a report from ElBaradei on Libya's atomic program.

US and British arms experts, as well as IAEA inspectors, have been active in Libya over the past two months. The IAEA inspectors have mainly been compiling inventories while the US and British teams have been carrying out the actual removing and destroying of equipment and documents, which have included blueprints for nuclear weapons.

The IAEA is due to issue the report on Libya -- as well as one on Iran's nuclear program -- this week to its 35-nation governing board ahead of the board's March 8 meeting, Gwozdecky said.

Libya is expected to win praise for cooperating in dismantling its programs to develop weapons of mass destruction, while the report on Iran should be more severe, diplomats close to the IAEA said.

Libya has been cooperating with the United States on disarmament while US officials claim that Iran is still hiding a secret nuclear arms program.

Diplomats said last week that IAEA inspectors in Iran had found blueprints for an advanced uranium enrichment centrifuge, a G-2 model, that Tehran had failed to declare even as it was claiming to be providing full disclosure on its atomic program.

Enriched uranium is used as fuel for nuclear reactors but can also be used for making atomic bombs.

Diplomats said the IAEA had used revelations made in dismantling Libya's atomic program to guide them to what the Iranians had.

"It's the same stuff that the Libyans had. It's really tracking along very much the same lines," a diplomat said.

Senior Iranian official Hossein Mussavian has acknowledged Iran is working on the G-2 advanced uranium enrichment centrifuge, but denied that such second-generation equipment had already been produced, according to a press report in Tehran Monday.

Diplomats said the discovery of Iran's study of the G-2 was not a "smoking gun" that the IAEA could use to take Iran before the UN Security Council, where it could face sanctions.

Nevertheless, it has raised alarms ahead of the publication of the new IAEA report, especially since Iran had halted uranium enrichment as a confidence-building measure.

The IAEA board had given Iran until last October 31 to reveal all details of its nuclear program.

The IAEA said in November that Iran had been hiding sensitive details, including the enriching of small amounts of uranium and plutonium, for 18 years.

WAR.WIRE