LONDON (Reuters) - Iran has denied entry to a senior U.N. nuclear inspector and cut back on multiple-entry visas that ease monitoring of its atomic sites as world pressure mounts on Tehran to stop enriching uranium, diplomats say.
As the clock ticks toward an Aug. 31 U.N. Security Council deadline for Iran to halt a nuclear fuel programme it deems a sovereign right, Tehran "has been complicating" U.N. watchdog operations in the country, said a Western diplomat.
Diplomats close to the International Atomic Energy Agency say Iran has not obstructed basic surveillance of nuclear sites declared under safeguard agreements and inspectors can still do their job.
But two said Iran recently refused the new visa for a veteran IAEA expert on centrifuges, machines with which Iran in April began enriching the fissile content in uranium for use as nuclear fuel.
The Western diplomat said the Islamic Republic was also increasingly giving single-entry visas to inspectors who had asked for multiple entries.
"This has (negatively) affected the work of four to five inspectors so far, and the Americans are getting quite nervous about the access issue," the diplomat told Reuters.
"It's not outright obstruction, but Iran is creating complications within its rights. They have reduced cooperation to a minimum under treaty obligations."
The Security Council has given Iran until Aug. 31 to shelve uranium enrichment in exchange for trade and other incentives.
Iran plans to give a firm answer to the incentives offer from six major powers on Tuesday.
Iranian Foreign Ministry spokesman Hamid Reza Asefi confirmed one inspector was "replaced on Iran's request ... (as) we were not happy with his activities. They were not in the framework of the inspector's duties". He did not elaborate.
Asefi told a Tehran news conference that Iran continued to give inspectors routine access to nuclear sites, but suggested this could change if the Security Council considered sanctions on Iran.
Diplomats did not know of a concrete reason given for Iran's rejection of the senior inspector.
Tehran says it wants nuclear fuel solely to generate electricity. Western powers note Iran has the world's second largest oil and gas reserves and suspect its nuclear quest is a disguised project to learn how to build atomic bombs.
Ahead of its official response on Tuesday to the Security Council deadline, Tehran has suggested it could discuss suspending enrichment as part of talks to implement the incentive, but not as a precondition as the powers demand.
IAEA chief Mohamed ElBaradei will issue a report to the Council on Aug. 31 certifying whether Iran has heeded the demand or not, based on the findings of senior inspector teams visiting Iranian atomic sites this month.
The inspector who was refused entry would have been in a team that went to Iran last week, the senior diplomat said.
More than 250 IAEA inspectors deal with Iran.
Tehran began narrowing cooperation with the IAEA in February when it withdrew its voluntary consent to short-notice inspections used to check allegations of secret military nuclear research under investigation since 2003.
In July, diplomatic sources said Tehran had banned the IAEA's Iran section head from visiting the country after he complained in a BBC documentary about inspectors being shadowed by Iranian security officials.
(Additional reporting by Parisa Hafezi in Tehran)