TEHRAN — The head of the International Atomic Energy Agency has warned that the "space for negotiation and diplomacy...is getting smaller" over Iran's advancing atomic program as conflicts in the Middle East rage on and Donald Trump gears up to return to the White House.

Rafael Grossi was visiting Tehran in an effort to restore his inspectors' access to the country's nuclear program and get answers to outstanding questions.

However, the remarks from both Grossi and his Iranian counterpart at a news conference suggested sizeable gaps still exist, even as some countries are pushing to take action against Iran at an upcoming IAEA Board of Governors' meeting.

"We know that it is indispensable to get, at this point of time, to get some concrete, tangible and visible results that will indicate that this joint work is improving (the) situation, is bringing clarification to things and in a general sense it is moving us away from conflict and ultimately war," Grossi said.

Since the collapse of the landmark nuclear deal in 2018, Iran has abandoned all limits on its nuclear activities and enriches uranium to up to 60% purity, which is near weapons-grade levels of 90%.

The Joint Comprehensive Plan of Action (JCPOA) came into force in 2016 and was signed by seven countries and the European Union. It saw Iran receive sanctions relief and other provisions for limits to its nuclear program.

But then President Donald Trump unilaterally withdrew the United States from the pact in 2018 calling it "the worst deal in history" and slapping crippling economic sanctions back on Tehran.

Surveillance cameras installed by the IAEA have been disrupted, while Iran has barred access to sites to some of the agency’s most experienced inspectors.

Iranian officials also have increasingly threatened that they could pursue atomic weapons, something the West and the IAEA has been worried about for years since Tehran abandoned an organized weapons program in 2003.

Speaking at a news conference with Mohammad Eslami of the Atomic Energy Organization of Iran, Grossi stressed that while the IAEA and Iran continued to negotiate, time was not necessarily on their side.

"The fact that international tensions and regional tensions do exist — this shows that the space for negotiation and diplomacy is not getting bigger, it is getting smaller," he said.

Before appearing with Eslami, Grossi met with Iranian Foreign Minister Abbas Araghchi, who later wrote in a post on X that, "differences can be resolved through cooperation and dialogue."

However, he warned Tehran was "NOT ready to negotiate under pressure and intimidation."

Some politicians have even suggested Iran abandon the Treaty on the Non-Proliferation of Nuclear Weapons, known as the NPT, and pursue the bomb.

Araghchi referred to Iran as "a committed member of NPT," though Eslami in his remarks warned Iran could retaliate if challenged at the upcoming IAEA Board of Governors' meeting.

Grossi acknowledged some nations were considering taking action against Iran.

"We have repeatedly said any resolution seeking to intervene in the Islamic Republic of Iran’s nuclear affairs will be definitely followed by immediate reciprocal steps and we will not allow them to (exert) this kind of pressure," Eslami said.

Journalists at the news conference, as well as Eslami, criticized Israel for its long-time sabotage and assassination campaign targeting Iran's nuclear program.

Some noted Israeli officials had threatened Iran's nuclear sites as targets for potential retaliation as Iran and Israel trade direct attacks amid the ongoing Israel-Hamas war in the Gaza Strip and Israel's ground and air offensive in Lebanon.

"The answer is in what we do here, what we, the IAEA, and Iran can do in terms of solving the questions at hand," Grossi said, describing "a situation of tension" with Iran's nuclear program at its centre.

"I am here to work with Iran, (to) try to find adequate solutions to ease tensions, to move forward. This is my target. This is my concern. And I am confident that we are going to be able to do it," he said.

But as the two men ended the news conference to shout questions from journalists, neither had offered any sign a breakthrough was imminent.

Grossi also met Thursday for the first time with reformist President Masoud Pezeshkian. He’s scheduled to visit Iran’s Fordo and Natanz nuclear enrichment sites on Friday. — Euronews