Iran’s parliament speaker Mohammad Baqer Qalibaf said the United States was signaling openness to negotiations while simultaneously planning military escalation, adding Tehran would not accept what he described as attempts at coercion.

His remarks came as thousands of U.S. Marines began arriving in the region, with the first contingents deployed aboard an amphibious assault ship, according to the U.S. military.

The conflict, triggered by U.S. and Israeli strikes on Iran on Feb. 28, has killed thousands and severely disrupted oil and liquefied natural gas supplies, particularly through the Strait of Hormuz, a critical artery for global energy shipments.

Foreign ministers from Pakistan, Saudi Arabia, Turkey and Egypt met in Islamabad to discuss pathways to de-escalation, with Pakistan positioning itself as a potential intermediary between Washington and Tehran. Pakistan’s Prime Minister Shehbaz Sharif held talks a day earlier with Iranian President Masoud Pezeshkian, while Foreign Minister Ishaq Dar conducted bilateral meetings with his Turkish and Egyptian counterparts ahead of broader consultations.

Parallel military-level engagements are also underway. Pakistan’s army chief Asim Munir remains in contact with U.S. Vice President JD Vance, according to a source familiar with the discussions, indicating ongoing coordination alongside diplomatic outreach.

A Turkish official said Ankara was working with partners on a proposal to reopen the Strait of Hormuz as part of confidence-building measures tied to a potential ceasefire.

The United States has previously outlined a 15-point ceasefire framework, including reopening the waterway and curbing Iran’s nuclear programme, though Tehran has rejected the proposal and advanced its own terms.

Despite diplomatic efforts, hostilities continued. Israel said it struck dozens of targets across Iran, including weapons production and storage facilities in Tehran, while Iranian media reported casualties from strikes on southern port infrastructure.

The conflict has expanded geographically, with Iran-linked Houthi forces launching attacks on Israel, raising concerns about renewed threats to commercial shipping routes. The Strait of Hormuz remains effectively closed, while risks are also rising around the Bab el-Mandeb Strait, a key gateway to the Suez Canal.U.S. officials, cited by the Washington Post, said the Pentagon was preparing for the possibility of prolonged ground operations, including special operations raids and conventional troop deployments, though it remains unclear whether President Donald Trump will authorize such action.

Secretary of State Marco Rubio said Washington could achieve its objectives without deploying ground forces but emphasized the need for military flexibility.Oil prices have surged toward $100 per barrel since the conflict began, reflecting supply disruptions and heightened geopolitical risk.

Iran has allowed limited passage for Pakistani-flagged vessels through the Strait of Hormuz, permitting two ships per day, according to Pakistani officials.

The conflict is also reverberating domestically in the United States, where protests have taken place in multiple cities amid growing public opposition.

With midterm elections approaching, the war has added pressure on the administration as it weighs military escalation against diplomatic resolution.

Air raid sirens sounded across Israel early on Sunday, warning of incoming Iranian missiles, after dozens of people were wounded overnight in separate attacks in the southern towns of Arad and Dimona. Israel’s military said it was carrying out strikes on Tehran hours after the Iranian attacks.

Trump on Saturday warned he would “obliterate” Iran’s power plants if Tehran did not fully reopen the Strait of Hormuz within 48 hours, marking a sharp escalation a day after suggesting the conflict could be wound down.

Iran responded on Sunday by warning it would strike U.S. infrastructure, including energy facilities in the Gulf, if Washington followed through on its threat. The warning came as U.S. Marines and heavy landing craft continued moving toward the region.

The exchange of threats has heightened fears that energy installations across key Gulf producers could become direct targets, widening the conflict beyond current theatres of engagement.

The escalating the crisis has disrupted markets, pushing fuel costs higher and intensifying concerns over global inflation. Analysts said the situation has introduced acute uncertainty into financial markets already strained by supply disruptions.

“President Trump’s threat has now placed a 48-hour ticking time bomb of elevated uncertainty over markets,” said Tony Sycamore, an analyst at IG.

He warned that failure to de-escalate could trigger sharp declines in global equities and further spikes in oil prices.

Oil prices rose on Friday to their highest levels in nearly four years after Iraq declared force majeure on oilfields operated by foreign firms, Israel struck a major Iranian gas field, and Tehran retaliated with attacks on neighbouring countries including Saudi Arabia, the United Arab Emirates, Qatar and Kuwait.

Iranian actions have effectively closed the Strait of Hormuz, a narrow passage that carries around a fifth of global oil and liquefied natural gas supplies, triggering what analysts describe as the most severe oil disruption since the 1970s.

The near-closure has also driven European gas prices sharply higher, with increases of up to 35% reported last week, reflecting the strait’s central role in global energy flows.

In a social media post late on Saturday, Trump reiterated his ultimatum, saying the United States would begin targeting Iran’s power infrastructure if the waterway was not reopened “fully” and “without threat” within the specified timeframe.

The Israeli Defense Forces said the attacks targeted “infrastructure of the Iranian regime” in the capital, without providing operational details. The strikes came a day after Trump publicly cautioned Israel against repeating attacks on Iranian natural gas facilities, highlighting emerging divergences within the U.S.-Israeli alignment.

Iran’s retaliation in recent days has expanded the conflict’s geographic scope, with Bahrain, Kuwait and the United Arab Emirates reporting missile activity early on Friday. The widening theatre of operations underscores the vulnerability of Gulf states as the confrontation increasingly targets strategic economic assets.

Iranian strikes earlier hit Qatar’s Ras Laffan Industrial City, a key hub processing roughly one-fifth of global liquefied natural gas supply. Damage to the facility is expected to take years to repair, according to initial assessments, amplifying concerns over long-term supply disruptions in global energy markets.

Saudi Arabia’s main Red Sea port was also attacked on Thursday, despite efforts to reroute exports away from the Strait of Hormuz, a critical maritime chokepoint that Iran has sought to pressure by threatening or disrupting transit.

Energy prices surged on Thursday following the strike on Qatar’s gas infrastructure, reflecting market anxiety over supply shocks. However, oil prices retreated on Friday after European countries and Japan signaled readiness to support maritime security operations to ensure continued passage through the Strait of Hormuz.

The United States also outlined measures to increase oil output, helping to offset immediate supply fears and stabilize market sentiment. The Strait remains a conduit for roughly one-fifth of global oil flows, making any disruption a significant risk to international energy stability.

The attacks on high-value energy infrastructure across the Gulf have highlighted both Iran’s retaliatory reach and the limitations of existing air defense systems in protecting dispersed, high-capacity facilities.

The conflict, which escalated after U.S. and Israeli strikes on February 28 following failed negotiations over Iran’s nuclear program, has since resulted in thousands of casualties and triggered cascading economic and security repercussions across the region.

Washington said it had not been informed in advance of Israel’s earlier strike on Iranian gas infrastructure, a development that adds complexity to coordination between the allies as the conflict evolves.