State media claims incident part of drill at Revolutionary Guards base in Karaj, which hosts nuclear centrifuge assembly facility previously targeted in drone strike

Report says inspectors from UN atomic agency made discovery last week, are probing if move was intentional; Tehran previously known to have enriched to 60%

IAEA flags 'substantial' revision to links between IR-6 cascades enriching uranium to 60%; Tehran claims report based on flubbed data from inspectors that was since corrected

Iranians inform IAEA they will install two new cascades of advanced IR-6 centrifuges at underground Natanz nuclear facility; move comes as agency votes to censure Tehran

International Atomic Energy Agency confirms machines moved to Natanz for better protection, after sabotage blamed on Israel at several plants

Iranian atomic energy organization says Tehran 'obliged to intensify security measures' by shifting some machinery to Natanz, which was also a target of reported Israeli attacks

Move comes just weeks after Tehran said it set up another site for producing centrifuges in Isfahan, where UN watchdog doesn't have access to data collected by its cameras

European diplomat says centrifuge plant at Karaj has been moved to 'better protected' facility in Isfahan; IAEA says cameras installed at new site

Tehran has denied the Karaj facility was hit in June drone strike

In one of his first speeches as PM, leader says that while Israel will defend itself, it will also work with allies to block an Iranian bomb, breaking from Netanyahu's policy