Western diplomats and nuclear inspectors who frequently travel to Tehran as part of the international effort against Iran's uranium enrichment activities say that "a sense of paranoia appears to have gripped the regime in recent months," the Daily Telegraph reported Friday.

“There has certainly been a change of mood since the start of the year,” a Vienna-based official told the paper's correspondent this week. “In the past they always appeared very self-confident and sure-footed in their dealings with foreign officials. Now they come across as very suspicious, and watch our every move.”

The report says that Tehran’s suspiciousness may explained by the fact that President Mahmoud Ahmadinejad and other officials realize that "they are running out of time in their negotiations with the West."