‘New cards on the battlefield’: U.S., Iran ratchet up rhetoric with peace talks in limbo

The U.S. and Iran escalated their war of words as a shaky ceasefire nears expiry, with each side raising the stakes ahead of a second attempt at reaching a peace deal.

Iran's parliamentary speaker, Mohammad Bagher Ghalibaf, appeared to up the ante in a social media post on Tuesday, criticising U.S. President Donald Trump for "imposing a siege and violating the ceasefire," and for seeking to turn the negotiation into "a table of surrender or to justify renewed warmongering."

Ghalibaf also suggested that Iran is holding fresh leverage in the standoff. "In the past two weeks, we have prepared to reveal new cards on the battlefield," Ghalibaf said, without elaborating. "We do not accept negotiations under the shadow of threats," he added.

The sharpened rhetoric came after Trump renewed his threat of bombarding Iran with overwhelming military force if no deal is reached, saying that "lots of bombs [will] start going off."

The status of further peace talks and other key details of the current relationship between the warring powers have grown increasingly opaque, with Trump vacillating between resuming saber-rattling rhetoric and indicating Washington's readiness for additional negotiations with Iran.

"This is the last chance to achieve an agreement before the ceasefire expires," Marc Sievers, former U.S. ambassador to Oman, said on CNBC's "Access Middle East" on Monday, warning that the stakes are high if Trump follows through with his threat of resuming military hostilities against Iran's power plants and bridges.

The escalation in tensions came as a U.S. delegation was preparing to travel back to Pakistan for a potential second round of peace talks. The American delegation "plans to travel to Islamabad soon," a source familiar with the matter told CNBC on Monday morning.

Iran, for its part, has repeatedly denied that it will participate in the meeting. A delegation from Tehran plans to travel to Islamabad on Tuesday for talks, according to The New York Times, citing two Iranian officials.

A first round of talks in Islamabad, led by Vice President JD Vance and U.S. special envoys Steve Witkoff and Jared Kushner, ended on April 12 with no resolution to thorny issues like Iran's nuclear program.** **

The U.S. and Iran agreed to a two-week ceasefire on the evening of April 7. The temporary truce has come under mounting strain throughout its short duration, with each side accusing the other of violating its terms.

In an interview with Bloomberg on Monday, Trump said the truce expires on "Wednesday evening Washington time," potentially buying additional hours for negotiations. Trump added he is unlikely to extend the Iran ceasefire beyond Wednesday and won't open the Strait of Hormuz until a deal with Tehran is reached.

When asked if he would expect the fighting to resume immediately if they fail to reach an agreement, Trump said, "If there's no deal, I would certainly expect."

Upcoming peace talks

A diplomatic roadmap, rather than a permanent settlement, is the most realistic outcome of the Islamabad talks, said Cornelia Meyer, chief executive of Meyer Resources. Referring to the Iran nuclear deal, which took more than two years of negotiation before reaching a preliminary framework in 2015, Meyer said that "expecting a real peace settlement is going too far."

Vance, along with officials from the National Security Council, the State Department, and the Pentagon, is reportedly part of the U.S. delegation heading to Pakistan for talks on Tuesday, according to multiple news outlets.

American negotiators may be at a disadvantage at the negotiating table with Iran's experienced diplomatic delegation — a team of professionals who "know their portfolios," said Alan Eyre, a former senior US diplomat who helped negotiate the 2015 Iran nuclear deal, while the U.S. side lacks comparable expertise in international relations.

Unless the U.S. brings "a team of competent experts whom they trust ... they're out of their league," said Eyre, adding that the "best possible, realistic outcome" from the potential talks would be an agreement on general principles and an extension of the ceasefire.

The fate of Iran's nuclear material will remain a key sticking point in negotiations. Trump said on Friday that Iran had agreed to transfer its stockpile of highly enriched uranium to the U.S., a claim that Iran denied within hours.

In a Truth Social post late Monday stateside, Trump repeated that the U.S. "Operation Midnight Hammer" — the June 2025 strikes targeting three facilities critical to Tehran's nuclear program — succeeded in creating a "total obliteration of the Nuclear Dust sites" and "digging it out will be a long and difficult process."

The U.S. and Iran have also been at an intense impasse over marine traffic through the Strait of Hormuz, with Trump vowing to keep in place a blockade of Iranian ports and Tehran reasserting military control of the crucial waterway. The chokepoint in normal times is the throughway for 20% of the world's oil and gas transits.

Further escalating tensions in the canal, the Iranian foreign ministry accused the U.S. of attacking an Iranian commercial vessel and demanded the release of its crew.

Over the weekend, the U.S. Navy fired on and seized an Iran-flagged cargo ship that had tried to bypass the blockade — the first significant encounter since the U.S. blockade began — while Tehran fired on two ships attempting passage, the latest escalation in the vital artery that put both sides on a collision course as the clock runs down on Islamabad.

"Any escalation, particularly military action around Hormuz, could trigger a renewed spike in oil prices and a broad risk-off move," said Lloyd Chan, senior currency analyst at MUFG Global Markets Research, noting that the murky outlook on peace talks left markets guessing on when energy shipments through the Strait of Hormuz could resume.

— CNBC's Kevin Breuninger contributed to this report.