Islamabad, Pakistan – Pakistan has rejected allegations that it had sheltered Iranian military aircraft from potential United States strikes as the fragile ceasefire it helped broker between Washington and Tehran appears increasingly at risk.

The Ministry of Foreign Affairs statement on Tuesday came hours after US President Donald Trump said the month-old truce was on “massive life support” as he dismissed Iran’s latest peace proposal as “a piece of garbage” that he had not even finished reading.

Trump’s remarks followed a report by CBS News on Monday saying Iran had moved several military aircraft, including an RC-130 reconnaissance plane, to Pakistan Air Force Base Nur Khan near Rawalpindi after the April 8 ceasefire, potentially shielding them from US attacks.

Pakistan’s Foreign Ministry on Tuesday called the report “misleading and sensationalised”, saying the aircraft had arrived as part of diplomatic logistics linked to talks in Islamabad between senior US and Iranian officials on April 11. Pakistan said both Iranian and US aircraft used the base.

“The Iranian aircraft currently parked in Pakistan arrived during the ceasefire period and bear no linkage whatsoever to any military contingency or preservation arrangement,” the ministry said.

The Foreign Ministry also pointed out that any significant foreign military presence at the base would be impossible to hide.

“Assertions suggesting otherwise are speculative, misleading, and entirely detached from the factual context,” it said, adding that Pakistan had “consistently acted as an impartial, constructive and responsible facilitator” throughout the process.

Washington unease

The denials, however, have done little to calm concerns in Washington.

A CNN report published hours after the CBS story said some Trump administration officials believed Pakistan has been sharing “a more positive version of the Iranian position with the US than what reflects reality” while questioning whether Islamabad was “aggressively conveying Trump’s displeasure”.

A Pakistani official told Al Jazeera that Islamabad has been as direct with both parties as any neutral arbiter could be because mediation requires impartiality to succeed rather than pushing agendas.

“Objective is to resolve the complex, historical, highly consequential conflict rather than earning brownie points or headline diplomacy,” the official said, speaking on condition of anonymity because the official was not authorised to speak to the media.

US Senator Lindsey Graham, a Trump ally and member of his Republican Party, called for “a complete reevaluation” of Pakistan’s mediator role, saying on X that he “would not be shocked” if the CBS report proved accurate.

Analysts, however, said the controversy was unlikely to significantly damage Islamabad’s position.

“Pakistan has done more than many had expected. Delivering a ceasefire in an environment marred by sheer distrust was no mean feat,” Syed Ali Zia Jaffery, deputy director at the Centre for Security, Strategy and Policy Research at the University of Lahore, told Al Jazeera.

He said the fact that both Tehran and Washington continued to rely on Pakistan suggested the allegations would have limited impact.

“As long as both capitals believe that Islamabad remains a dependable facilitator and mediator, such reportage won’t have any impact. This is a multiparty war, which leaves a lot of room for spoilers to obfuscate things,” Jaffery said.

Talks at an impasse

The immediate trigger for the latest tensions was Washington’s rejection of an Iranian peace proposal delivered through Pakistan on Sunday.

Iranian state media said Tehran’s terms included US war reparations, full Iranian sovereignty over the Strait of Hormuz, an end to sanctions and the release of its frozen assets while insisting nuclear negotiations be deferred to a later stage.

Trump, posting on his Truth Social platform, described the proposal as “TOTALLY UNACCEPTABLE”.

“I would say the ceasefire is on massive life support,” he said later in the Oval Office, describing the situation as one “where the doctor walks in and says, ‘Sir, your loved one has approximately a 1 percent chance of living.’“

Iranian Ministry of Foreign Affairs spokesman Esmaeil Baghaei rejected that characterisation, calling the proposal “reasonable and generous” and saying Tehran had demanded “only Iran’s legitimate rights”.

Parliament Speaker Mohammad Bagher Ghalibaf, Iran’s lead negotiator, struck a more defiant tone.

“Our armed forces are prepared to deliver a lesson-giving response to any aggression,” he wrote on social media on Monday. “There is no alternative but to accept the rights of the Iranian people as laid out in the 14-point proposal.”

The core disagreements remain unchanged.

Washington wants Iran to explicitly abandon its nuclear programme and surrender its stockpile of uranium enriched to 60 percent, near weapons-grade levels.

Tehran insisted nuclear negotiations can only follow the lifting of sanctions and the end of the US naval blockade imposed on its ports on April 13.

Since the Islamabad talks ended without an agreement between the US and Iran on April 12, Pakistan has largely acted as an intermediary, carrying proposals between the two sides, which have not met directly since.

On May 4, Pakistani Deputy Prime Minister and Foreign Minister Ishaq Dar spoke with Iranian Foreign Minister Abbas Araghchi about Islamabad’s mediation efforts.

The same day, 22 crew members on board the Iranian container ship MV Touska, which had been captured by US forces, were evacuated to Pakistan before being transferred to Iran in what Islamabad described as a confidence-building measure coordinated with both sides.

Qatar has also backed the mediation effort. US Secretary of State Marco Rubio met Qatari Prime Minister Sheikh Mohammed bin Abdulrahman bin Jassim Al Thani in Miami, Florida, on Saturday with Doha pledging support for “mediation efforts led by Pakistan”.

Jaffery said the ceasefire had been “practically violated” once the US imposed its naval blockade although both sides have since sought to avoid a return to full-scale war.

“I do not think that kinetic engagement is imminent. What is likely to intensify is harassment and interdiction along the Strait of Hormuz,” he said.

Muhanad Seloom, a nonresident senior fellow at the Middle East Council on Global Affairs, agreed.

What is likely in the next few days, he said, “is narrow kinetic action, likely against IRGC [Islamic Revolutionary Guard Corps] assets harassing Hormuz traffic, calibrated so Iran can absorb it without striking US bases in the Gulf”.

Seloom pointed to recent comments from US Energy Secretary Chris Wright on going “back to the military method to open the strait”. That, the analyst told Al Jazeera, revealed that the US was looking at “a Hormuz operation, not regime confrontation”.

The road ahead

Trump is expected to discuss the Iran crisis with Chinese President Xi Jinping during a visit to Beijing this week as Washington hopes Beijing could use its influence with Tehran. China is Iran’s biggest economic and strategic partner.

Araghchi met Chinese Foreign Minister Wang Yi last week in Beijing, where China reaffirmed its “strategic partnership” with Iran while calling for a diplomatic solution.

The Iranian foreign minister is also expected to attend a meeting of BRICS foreign ministers in India on Thursday and Friday alongside the top diplomats of Saudi Arabia and Egypt, both involved in backchannel diplomacy.

“Trump is going to Beijing in a weaker position,” Jaffery said, adding that China was unlikely to resolve Washington’s Strait of Hormuz dilemma.

On Araghchi’s diplomatic outreach, he said, Tehran was seeking “a buy-in for a broad-based agreement, not a ceasefire”.

Pakistan’s importance, he argued, would remain intact regardless of which diplomatic channels emerged.

“Both sides coordinate and consult with it,” he said.

Seloom said the increasing number of countries getting involved in the mediation was better for the prospects of peace.

“For the ceasefire, this is actually stabilising. More parties with skin in the game raise the cost of collapse for everyone,” he said.

Meanwhile, Israeli Prime Minister Benjamin Netanyahu said in an interview with the CBS News programme 60 Minutes that aired on Sunday that Israel viewed the conflict as unresolved.

If Iran’s nuclear material could not be removed through negotiations, he said, Israel and the US agreed “we can re-engage them militarily”.

Former Qatari Prime Minister Sheikh Hamad bin Jassim Al Thani offered a starker assessment in remarks to Al Jazeera on Monday.

The weaponisation of the Strait of Hormuz, he said, was “the most dangerous outcome” of the conflict, warning that the crisis would outlast any ceasefire.