The U.N. nuclear watchdog agency on Friday suspended nearly half of the technical aid it now provides Iran, in line with sanctions imposed on the country for its refusal to suspend uranium enrichment.

As IAEA chief Mohamed ElBaradei issued the report to his agency's 35-nation board, Iran's chief nuclear negotiator abruptly canceled meetings both with ElBaradei in Vienna and with senior European leaders in Munich, on the sidelines of a security conference in the German city.

Organizers of the Munich conference said negotiator Ali Larijani canceled because of an unspecified illness, whereas IAEA officials said they were told he was not coming for "technical reasons."

"The official explanation is that he got sick," said Horst Teltschik, the Munich conference organizer.

Larijani's meetings with German Foreign Minister Frank-Walter Steinmeier and Javier Solana, the chief foreign policy envoy for the European Union would have been the first with senior Western officials since negotiations with Solana collapsed last year over Tehran's refusal to suspend enrichment, a potential pathway to nuclear arms.

The Vienna-based IAEA already suspended aid to Iran in five instances last month in line with Security Council sanctions calling for an end to assistance for programs that could be misused to make atomic weapons. Diplomats emphasized that the freeze was temporary and subject to review and approval by the 35-nation board of the IAEA next month.

On Friday, the agency fully or partially suspended another 18 projects that it deemed could be misused. Those too were subject to review and approval by the board.

Iran gets IAEA technical aid for 15 projects and 40 more that involve other countries. The suspensions were across the board but in the case of projects involving other countries affected only Iran.

A diplomat familiar with the issue said the United States — along with key allies — had been looking to have up to half of the projects involving only Iran canceled, restricted or more closely monitored.

A U.S. official said Washington's position on what projects should be affected was "very similar" to that of the European powers, Britain, France and Germany.

The officials all spoke on condition of anonymity in return for divulging confidential information

The United States, Russia, China, Britain, France and Germany all want Iran to suspend its enrichment program and have acted as a group in trying to engage Tehran on the issue. But their approaches and priorities have differed over the past year.

Russian and Chinese reluctance to impose harsh sanctions on Tehran — as initially demanded by Washington — have created the greatest pressures. Both nations share economic and strategic interests with Iran.

Differences over how severely to punish Tehran for its refusal to suspend enrichment led to months of disputes before agreement was reached in December on a Security Council resolution imposing limited sanctions that fell short of the harsher measures sought by the Americans.

The sanctions include a review of technical aid to Iran — programs meant to bolster the peaceful use of nuclear energy in medicine, agriculture or power generation.

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