The inspectors arrived to install surveillance equipment and lift metal seals on the plant, whose reopening risks putting Tehran on a collision course with Europe and the United States over its nuclear programme.

The official did not specify when the seals would be lifted.

The officials had arrived in Iran late on Sunday, two days before an extraordinary meeting of the IAEA called by the European Union after Tehran announced it would resume the ultra-sensitive nuclear activity.

Earlier the IAEA, which had placed the metal seals at the plant, has said that its inspection team will put in place the equipment by the middle of the week. Iran has always emphasised it wants to break the seals in concert with the IAEA.