The team arrived in Baghdad on Friday for the first visit by monitors from the Vienna-based organization since U.N. weapons inspectors left the country in late 1998 on the eve of U.S.-British airstrikes.
"We will start our first round this morning," was all that Ahmad Abuzahra, head of the International Atomic Energy Agency, said as he and five monitors left their hotel.
Their job is to make sure Iraq's nuclear stocks are not used for military purposes.
Abuzahra said Friday that the inspection was not part of the supervision regime imposed on Iraq by the United Nations after the 1991 Gulf War over Iraq's invasion of Kuwait.
"We are here to perform routine physical inventory checking for nuclear material," he said.
The inspection, he added, was part of the monitoring program imposed on all signatories to the nuclear nonproliferation treaty. Iraq signed in 1968.
The agency visit should have taken place in late 1999, but Iraq, without explanation, delayed issuing visas to the inspectors. IAEA spokesman David Kyd had said the visas may have been held back because of the debate in the U.N. Security Council about setting up a new organization to ensure that Iraq does not have mass-destruction weapons.
The IAEA is also responsible for stripping Iraq of its potential to acquire or produce nuclear weapons. Until the 1998 departure of U.N. weapons inspectors, the IAEA used to carry out stringent searches of Iraq's nuclear sites and stockpiles.
The agency reported that Iraq no longer had the ability to produce nuclear weapons, but said Baghdad still had to answer questions about its past atomic program.
In December, the U.N. Security Council passed a resolution that charges the agency with the task of monitoring Iraq's nuclear facilities.