DUBAI, United Arab Emirates -- Japanese Prime Minister Shinzo Abe's trip to Tehran represents the highest-level effort yet to de-escalate tensions between the U.S. and Iran as the country appears poised to break the 2015 nuclear deal it struck with world powers that America earlier abandoned.
But while Abe's trip to Iran marks the first visit of a sitting Japanese premier in the 40 years since the Islamic Revolution, it remains unclear if he'll end up going home with any success.
Iran is threatening to resume enriching uranium closer to weapons-grade level on July 7 if European allies fail to offer it new terms. While President Donald Trump says he wants to talk to Tehran, the U.S. has piled on sanctions that have seen Iran's rial currency plummet along with its crucial oil exports.
The U.S. also has sent an aircraft carrier and B-52 bombers to the region, along with hundreds more troops to back up the tens of thousands already deployed across the Middle East. The U.S. blames Iran for a mysterious attack on oil tankers off the coast of the United Arab Emirates, while Iranian-backed rebels in Yemen continue to launch coordinated drone attacks on Saudi Arabia.
The stakes, analysts say, couldn't be higher.
"Just going to Iran doesn't resolve any problem," said Kazuo Takahashi, an Open University of Japan professor of international politics and expert on the Middle East. "He would have to help open a path of dialogue between the U.S. and Iran, and that could be a major risk."
Iran's nuclear deal, agreed to at the time by China, Russia, France, Germany, the United Kingdom and the U.S., saw Tehran agree to limit its enrichment of uranium exchange for the lifting of crippling sanctions. Western powers feared Iran's atomic program could allow it to build nuclear weapons, although Iran long has insisted its program was for peaceful purposes.
In withdrawing from the deal last year, Trump pointed to the accord not limiting Iran's ballistic missile program and not addressing what American officials describe as Tehran's malign influence across the wider Mideast. Those who struck the deal at the time described it as a building block toward further negotiations with Iran, whose Islamic government has had a tense relationship with America since the 1979 takeover of the U.S. Embassy in Tehran and subsequent hostage crisis.
Trump spoke Tuesday with Abe, said Yoshihide Suga, Japan's chief Cabinet secretary. Suga declined to give any details about what they discussed. Abe also in recent days spoken with Israeli Prime Minister Benjamin Netanyahu, Saudi Crown Prince Mohammed bin Salman and Abu Dhabi's Crown Prince Sheikh Mohammed bin Zayed Al Nahyan, all of whom are fierce critics of Iran.
"Taking into account the current status of rising tension in the Middle East, we hope to ease tensions through leader-level talks with Iran, a regional powerhouse," Suga said.
Middle East peace is a must for Japan, which gets most of the oil fueling its economy from there. Japan had once purchased Iranian oil, but it has now stopped because of American sanctions. Recent threats from Iran to close off the Strait of Hormuz, the narrow mouth through which a third of all oil traded by sea passes, has raised concerns.
Abe is scheduled to see Iranian President Hassan Rouhani, a relative moderate within Iran's Shiite theocracy, as well as Supreme Leader Ayatollah Ali Khamenei.
Already though, Iran says it quadrupled its production of low-enriched uranium. Yukiya Amano, the director-general of the U.N.'s nuclear watchdog agency that monitors Iran's nuclear deal, acknowledged Monday that Tehran has increased its production. However, Amano said he hadn't spoken recently with Abe.
Meanwhile, U.S. sanctions have cut off opportunities for Iran to trade its excess uranium and heavy water abroad, putting Tehran on course to violate terms of the nuclear deal regardless.
Hard-liners within Iran already have dismissed Abe's trip.
"Just like the nuclear deal . helped improved the country's economy, visits by people such as the Japanese prime minister will improve the livelihood of the people," the hard-line Kayhan newspaper sarcastically offered in an editorial Tuesday.
It remains unlikely Iran will want to engage in direct talks with the U.S. Iranian Foreign Minister Mohammad Javad Zarif, an American-educated diplomat key in negotiating the nuclear deal, openly threatened the U.S. during a news conference Monday with German Foreign Minister Heiko Maas.
"Mr. Trump himself has announced that the U.S. has launched an economic war against Iran," Zarif said. "The only solution for reducing tensions in this region is stopping that economic war."
Zarif also warned: "Whoever starts a war with us will not be the one who finishes it."
However, Iran on Tuesday did release U.S. permanent resident Nizar Zakka, a Lebanese-born internet advocate imprisoned for years in Tehran on internationally criticized spying charges. Zakka had done contract work for the State Department.
And overall, Iran risks little in inviting Abe to the country, said Henry Rome, an analyst with the Eurasia Group.
"Khamenei and Rouhani get to show the beleaguered population that despite extreme economic pressure, top world leaders are still willing to visit Iran," Rome wrote Monday. "And Tehran can probe for opportunities to expand its trade relationship with Tokyo, although options are quite limited."
Yamaguchi reported from Tokyo. Associated Press writer Amir Vahdat in Tehran, Iran, contributed.