Billions in frozen assets, an ambiguous nuclear program and a $300 billion reconstruction fund are just a selection of the high-stakes issues facing U.S. and Iranian negotiators over the next few months as both sides look to find an end to the war and get the best deal possible.

U.S. and Iranian officials are deep into the 60-day negotiating period outlined in the Islamabad Memorandum of Understanding, signed by both parties last month, but talks have already faced serious setbacks.

What began as public disagreements over interpretations of the memorandum following the first round of talks in Switzerland has resulted in both sides exchanging fire in the Strait of Hormuz, which Iran has increasingly used as a point of leverage.

The hiccups have led some observers to speculate on whether the two sides will reach an agreement at all.

“It’s a great space to have those talks, but I just think it’s more, for me, like a prolonged ceasefire,” said Bamo Nouri, senior lecturer in international relations at the University of West London. “I wouldn’t call it anything more than an extended ceasefire and an opportunity to replenish at a time when things are critical.”

Under the memorandum’s terms, the U.S. and Iran are expected to hammer out a final deal on a regional ceasefire, a $300 billion reconstruction plan, sanctions relief, the future of Iran’s nuclear program and the status of Iran’s frozen assets.

Even the most straightforward provisions of the memorandum, the full regional ceasefire, are facing extensive challenges.

In addition to the U.S. and Iran exchanging strikes over the Strait of Hormuz last week, Israel’s assault on the Iran-backed Hezbollah militants in Lebanon has threatened to upend the peace process.

Despite the memorandum calling for a ceasefire on all fronts, including in Lebanon, Israeli officials have said they have no intention of abiding by an agreement that they had no say in crafting.

Israeli Prime Minister Benjamin Netanyahu and Defense Minister Israel Katz have insisted they’re prepared to strike at Hezbollah despite the U.S.-Iran and Israel-Lebanon ceasefires.

Israel has been at war with Hezbollah in Lebanon since early March, when the terrorists launched rockets into Israeli territory following the death of Iran’s leader, Ali Khamenei.

While Israel’s attacks against Hezbollah enclaves have tapered off since the memorandum was finalized, its troops still hold significant territory in southern Lebanon and have refused to withdraw.

Israel’s infrequent attacks against Hezbollah and the country’s refusal to withdraw its troops from Lebanon have frustrated Iranian officials, who have threatened to stop negotiations if the U.S. does not restrain Mr. Netanyahu.

There’s also been wide public disagreement over possible sanctions relief, with Iranian officials asserting that Western sanctions relief is all but guaranteed. But Trump administration officials have reassured critics that Tehran will not see any relief unless it complies with certain U.S. demands.

Namely, Vice President J.D. Vance, who was present during the first round of direct negotiations last month, floated the idea of requiring Iran to use its billions of dollars of frozen assets to purchase American farm goods.

Tehran, however, issued a public rebuff on the suggestion, injecting fresh uncertainty into the prospects for upcoming talks on easing sanctions.

Washington, in particular, has already faced intense criticism from Iran hawks who say the memorandum of understanding could give Tehran access to billions of dollars in frozen assets and oil revenue.

Hawks have also said the memorandum fails to address Iran’s support for proxy organizations like Hamas, Hezbollah and the Houthis and does not mention Tehran’s ballistic missile or drone programs.

Iran, for its part, views the frozen assets as its own money and therefore has less room to negotiate.

“The Iranian argument is, well, that’s our money anyway, you know, doesn’t make sense kind of thing. So that’s a massive sticking point. I don’t see how that’s going to get resolved easily,” Mr. Nouri said. “Iran and the U.S. still have more differences between them, apparent now and out in the flesh of agreement, than they did even at the very early stages of negotiations, before the bombing started.”

Questions also remain over the $300 billion reconstruction fund, outlined in the memorandum. Mr. Vance said last month that the U.S. would not contribute to the investment and that Gulf nations would take the lead.

But Gulf leaders, Saudi Arabia, the United Arab Emirates and Qatar, have remained relatively quiet on the issue, refusing to commit without certain guarantees from Iran and the U.S.

Debates over sanctions relief and a ceasefire in Lebanon have all come before negotiators begin discussing Iran’s nuclear ambitions, over which the U.S. and Israel launched the war.

Unlike in 2015, when the Obama administration offered extensive sanctions relief in exchange for limits on Iran’s nuclear enrichment capabilities, Tehran’s proven ability to close the Strait of Hormuz leaves Washington with comparatively less leverage.

“JCPOA was giving Iran sanctions relief specifically to what Iran was willing to do, reducing the size of its nuclear program,” said Alex Vatanka, senior fellow at the Middle East Institute. “So now Iran is getting something just because of its geography, just because it’s the country that sits to the north of the Strait of Hormuz.”

Iran closed the strait in early March, shortly after the U.S. and Israel launched strikes on key military and political targets. At least 20% of the world’s oil travels through the waterway annually, and its closure caused international oil prices to skyrocket.

It also forced average U.S. gas prices to increase dramatically for weeks, reaching as high as $4.50 a gallon in May, putting political pressure on President Trump to end the war and reopen shipping.

That shift has left negotiators without a clear mechanism for tying sanctions relief to nuclear concessions, even as the physical status of Iran’s program remains murky.

U.S. and Israeli strikes last year damaged key Iranian facilities at Fordow, Natanz and Isfahan, but American officials have offered conflicting assessments of how much enriched uranium and centrifuge capacity survived.

Tehran, for its part, has not allowed International Atomic Energy Agency inspectors back into the country since the war began, leaving Washington to negotiate over a program it cannot independently verify.

That ambiguity could prove an issue for the U.S. as the Trump administration tries to quell the fears of critics who want Iran to abandon its nuclear program. Mr. Trump has repeatedly said he would not let Iran have a nuclear weapon.

Over the years, Iran has insisted that it’s not looking to secure nukes and that its program is entirely peaceful. When the JCPOA was active, Iran enriched uranium at civilian levels, but after Mr. Trump pulled the U.S. out of the agreement, Tehran’s enrichment levels inched closer to weapons-grade.

U.S. negotiators tried to secure severe limits on Iran’s nuclear program last year, before the June war, and again before the more recent conflict. Both times, Iranian representatives reportedly ceded ground on limits on enrichment but stopped short of agreeing to eliminate the program.

Still, experts doubt that the U.S. will resume full military operations against Iran to force a concession on the nuclear issue, citing Mr. Trump’s preoccupation with oil prices and other economic concerns.

“He doesn’t have to worry too much about Iran’s nuclear program at this point,” Mr. Vatanka said. “What he worries about is the economic impact of this war.”