VIENNA (Reuters) – A U.S. think-tank has published satellite images which it says underscore suspicions that Iran is trying to destroy evidence of possible nuclear weapons-related research at a site that U.N. inspectors have not been allowed to visit.

The Institute for Science and International Security (ISIS) posted the pictures on its website hours after the U.N. nuclear watchdog showed diplomats similar images that western envoys said indicated a clean-up at the Parchin military facility.

VIENNA (Reuters) – A U.S. security institute has published satellite images which it said increased concerns that Iran was trying to “destroy evidence” of suspected past research relevant for developing a nuclear weapons capability, a charge Tehran dismisses.

The Institute for Science and International Security (ISIS) posted them on its website hours after diplomats said the U.N. atomic watchdog showed what appeared to be similar imagery at a closed-door briefing in Vienna.

VIENNA (Reuters) – U.N. nuclear inspectors showed new satellite imagery on Wednesday indicating that two side buildings had been dismantled and other possible clean-up work undertaken at an Iranian military site they want to visit, Western diplomats said.

One image from May 25 showed signs that “ground-scraping activities” had taken place at the Parchin facility as well as the presence of bulldozers, according to diplomats who attended a closed-door briefing by U.N. nuclear agency officials.

VIENNA (Reuters) – U.N. nuclear inspectors showed new satellite imagery on Wednesday indicating that two side buildings had been dismantled and other possible clean-up work undertaken at an Iranian military site they want to visit, Western diplomats said.

One image from May 25 showed signs that “ground-scraping activities” had taken place at the Parchin facility as well as the presence of bulldozers, according to diplomats who attended a closed-door briefing by U.N. nuclear agency officials.

VIENNA (Reuters) – Iran has significantly stepped up its output of low-enriched uranium and total production in the last five years would be enough for at least five nuclear weapons if refined much further, a U.S. security institute said.

The Institute for Science and International Security (ISIS), a think-tank which closely tracks Iran’s nuclear program, made the analysis on the basis of data in the latest quarterly U.N. watchdog report which was issued on Friday.

VIENNA (Reuters) – United Nations nuclear inspectors have found uranium particles refined to a higher-than-expected level at an underground site where Iran has installed more than 50 percent more enrichment centrifuges, a U.N. watchdog report said on Friday.

It said Tehran had told the U.N. agency that the presence of traces of highly refined uranium – still well below potential nuclear weapons-grade material – “may happen for technical reasons beyond the operator’s control”.

VIENNA (Reuters) – U.N. nuclear inspectors have found uranium traces in an Iranian underground site refined to a somewhat higher level than the enrichment work normally done there, but still well below the weapons-grade threshold, diplomatic sources said on Friday.

One source said the higher level detected at the Fordow site – where Iran has declared it is refining uranium to a fissile concentration of 20 percent only – was believed to be between 20 and 30 percent, making clear this was not a big difference.

VIENNA (Reuters) – A U.N. watchdog report is expected to show that Iran has installed more uranium enrichment centrifuges at an underground site, potentially boosting output capacity of nuclear work major powers want it to stop, Western diplomatic sources say.

Two sources said the Islamic state may have placed in position nearly 350 machines since February – in addition to the almost 700 centrifuges already operating at the Fordow facility – but that they were not yet being used to refine uranium.