Western nations are “poisoning the environment” at a key meeting of the International Atomic Energy Agency by underestimating initial successes of an agency probe into his nation’s nuclear past, a senior Iranian envoy said Wednesday.

Ali Ashgar-Soltanieh, Iran’s chief delegate to the agency, spoke outside a 35-nation IAEA board meeting as it prepared to end its review of an agency report describing Iran’s cooperation with the probe as “a significant step forward.”

But the U.S. and its western allies continue to suspect that Iran is exploiting a plan outlining what questions Iran will answer and when as a smoke screen to deflect attention from its continued defiance of a Security Council ban on enrichment, a potential pathway to nuclear arms.

A statement by the European Union on Tuesday appeared to reflect that concern; it focused mostly on Iran’s defiance of a U.N. Security Council ban and gave relatively short shrift to IAEA chief Mohamed ElBaradei’s reported successes in prying answers from Iran.

The statement said the EU has “taken note” of those efforts – the most noncommittal of diplomatic terms that falls substantially short of approval.

A diplomat who spoke to the AP on condition of anonymity, because of a bar on divulging proceedings at the closed meeting, said ElBaradei subsequently left the conference to show his disapproval of the EU’s lukewarm approach.

“He was disappointed,” said the diplomat.

Soltanieh, in comments to The Associated Press, called the West’s approach “regrettable,” saying: “It has poisoned the environment.”

“If they underestimate and question this pact, they are weakening the IAEA,” he said.

Backing Iran, non-aligned nations on Tuesday rejected “interference” – an allusion to U.S. concerns about the International Atomic Energy Agency’s newest Tehran probe.

Norma Miguelina Goicochea Estenoz of Cuba also expressed support for the work of the agency and Mohamed ElBaradei in her capacity as head of the agency’s non-aligned board members.