Just days after President Trump announced the US withdrawal from the 2015 Iran nuclear deal brokered under Obama, the U.N.'s top nuclear inspector has abruptly and unexpectedly resigned after a tense week in which Iran's facilities have again become the focus of the organization's mission.

Veteran nuclear weapons inspector Tero Varjoranta announced his resignation as chief inspector of the International Atomic Energy Agency (IAEA) effective May 11th but didn't provide explanation, only citing "confidential personal matters" according to the AP.

Tero Varjorantadeputy (pictured furthest left), director general of the IAEA and head of its Department of Safeguards, sitting next to IAEA Director General Yukiya Amano. Image source: IAEA

Varjoranta, a Finn, served for five years as a deputy director general of the IAEA and head of its Department of Safeguards, which verifies countries’ compliance with the nuclear Non-Proliferation Treaty.

The AP further reports:

Varjoranta, who was in the role for almost five years, will be replaced temporarily by Massimo Aparo, an Italian nuclear engineer who was most recently the agency’s top inspector for Iran. The move comes just days after U.S. President Donald Trump announced the United States would withdraw from the 2015 Iran nuclear accord designed to keep Tehran’s atomic weapons program in check.

The Vienna-based IAEA is the U.N.'s top nuclear watchdog which coordinates in tandem with U.N. decisions and directives, and hasn't been shy in stating it's official position of finding no evidence showing Iran to be in breach of the nuclear deal.

Tero Varjoranta in 2014. Image via AFP/Getty

Indeed the very day after Israeli Prime Minister Netanyahu's televised speech claiming "evidence" that Iran is actually hiding an active nuclear program, the IAEA issued an assessment directly negating Israel's claims, firmly asserting that there are "no credible indications" supporting the charge of a continued illegal Iranian nuclear weapons program after 2009. Netanyahu has long maintained Israel's position that the nuclear deal “doesn’t block Iran’s path to the bomb, but actually paves it,” and has sought all available means to dismantle it.

According to the AP summary of that IAEA assessment:

The U.N. nuclear agency says it believes that Iran had a “coordinated” nuclear weapons program in place before 2003, but found “no credible indications” of such work after 2009... The documents focused on Iranian activities before 2003 and did not provide any explicit evidence that Iran has violated its 2015 nuclear deal with the international community.

Though IAEA leadership is now being tight-lipped about the sudden transition in leadership — notably not a single among the dozens of international press articles have given any hint as to the specifics — the past week has brought intense pressure to bear on the U.N. mission which ensures Iran's compliance to the Joint Comprehensive Plan of Action (JCPOA) terms.

The original brokers still backing the deal include the United Kingdom, Russia, France, China, and Germany — all signatories — with Germany, France, and Russia specifically warning this week that US withdrawal could further destabilize the Middle East.

This warning already seems to be materializing with Syria/Iran and Israel exchanging rocket fire this week, and as all signs point to further escalation.

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Meanwhile, Tehran has repeatedly affirmed its position that the existing terms of the JCPOA are non-negotiable.

In what's being widely described as a last-ditch effort to salvage the deal Iran's foreign minister Mohammad Javad Zarif has this weekend embarked on a tour of global capitals. On Saturday Iran announced the initiative on orders from President Hassan Rouhani for FM Zarif to visit European countries, China and Russia in the coming weeks to negotiate ensured continuance of the deal.

President Rouhani said, “If at the end of this short period we conclude that we can fully benefit from... [the nuclear accord] the deal would remain."

Iran is seeking to protect its economy from aggressive impending new US sanctions, especially key sectors like oil, which many analysts say can survive and flourish so long as European countries uphold their end of the agreement, in spite of the US now threatening sanctions against countries that continue to deal with Iran.

Likely the other five signatories will continue to honor the deal, but it will be interesting to see which European powers eventually cave under US pressure, at which point they might only pay lip service to the terms of the agreement while gradually rolling back economic and tried ties with Iran.

No doubt both Israel and the United States are even now behind the scenes maneuvering to make this happen — a likely reason for IAEA chief inspector Tero Varjoranta's shock resignation in the first place.

But meanwhile in Tehran, the clerics look preoccupied with other things at the moment...

Iran Supreme Leader Khamenei having some quality time; checking out a translation of "Fire And Fury" at Tehran book fair. HT @pooriast pic.twitter.com/dOx1wYSHuc — Hadi Nili (@HadiNili) May 11, 2018

Will Zarif's international lobbying efforts save the deal in spite of US withdrawal? The coming weeks will tell, unless war breaks out first.