Iran’s armed forces escalate threats as Khamenei rejects latest US proposal

The Islamic Republic Armed Forces General Staff, Iran’s highest military authority tasked with coordinating the conventional army (Artesh) and the Islamic Revolutionary Guard Corps (IRGC), issued a threatening statement on June 4 amid stalled nuclear negotiations with the United States. The statement declared that “by standing firm against [US] threats,” the Iranian armed forces under the command of Supreme Leader Ali Khamenei “are ready with exemplary power to confront the enemies.”

The announcement came after Khamenei rejected Washington’s latest nuclear proposal in a June 4 sermon. He condemned the US demand for the complete dismantlement of Iran’s nuclear program, accusing the West of fixating on enrichment. “Enemies are focused on enrichment,” Khamenei said, dismissing the idea of operating “a hundred nuclear plants without enrichment” as senseless. He then issued a defiant warning. “Our answer to America is clear,” he said, adding that the “Americans and Zionist” officials behind the proposal “should know they cannot do a damn thing.”

The US proposal, delivered to Tehran on May 31, reportedly permits limited low-level uranium enrichment in Iran for an unspecified period but imposes strict conditions: dismantling key conversion infrastructure, halting centrifuge research and development, and banning new enrichment sites. It envisions a regional consortium, restricts enrichment to civilian use, caps levels at 3 percent, and renders underground facilities non-operational. Though enrichment is allowed in principle, the plan effectively requires Iran to dismantle existing infrastructure until the new consortium is in place.

Ali Shamkhani, a senior advisor to Khamenei and a key figure on the nuclear file, rejected the US proposal as unserious on June 4, calling its architects “amateur.” Shamkhani criticized the absence of any reference to sanctions relief—“an essential issue for Tehran”—and firmly rejected the goal of full disarmament. “America’s objectives of dismantling its nuclear program and reducing uranium enrichment to zero would not materialize,” Shamkhani stated.

Iran has grown increasingly skeptical of the nuclear talks, which ended in Rome without progress. On May 23, Iranian state outlets reported that US envoy Steven Witkoff had left the talks ahead of schedule, while CNN reported that officials in Tehran saw little chance of a breakthrough. Khamenei reinforced this bleak outlook in a May 20 address, denouncing Washington’s demands. That message was echoed on May 22 by Foreign Minister Abbas Araghchi, who ruled out any concessions on uranium enrichment.

In line with the Armed Forces’ statement, other branches of Iran’s military escalated their rhetoric. Defense Minister Brigadier General Aziz Nasirzadeh stated on June 4 that “Iran’s power deters Israel from issuing threats,” dismissing recent Israeli warnings as “baseless.” That same day, IRGC Navy Commander Commodore Alireza Tangsiri vowed a “harsh response” to any naval aggression and praised the Tehran-backed Yemeni Houthis for their ongoing attacks against Israel, which have continued almost daily since May.

State media further amplified the regime’s messaging, broadcasting a propaganda video showcasing Iran’s latest unmanned aerial vehicle (UAV). The footage featured the Jas-313 bomber UAV, capable of flying at 45,000 feet with a top speed of Mach 0.8 and an endurance of one hour. The IRGC Navy employs the drone for both reconnaissance and strike missions, and one source claimed the Jas-313 is designed to evade radar detection.

Iran has moved beyond rhetoric and taken concrete steps to reinforce its air defense posture amid growing concerns that failed nuclear negotiations could trigger a US or Israeli military strike. The regime’s air defense network suffered significant losses during Israeli air campaigns in April and October 2024, which damaged or destroyed most of its surface-to-air missile systems, including Russian-supplied S-300 batteries and associated radar units. In response, Tehran has reportedly redeployed air defense assets around sensitive nuclear facilities such as Natanz and Fordow.

Recent public displays suggest an effort to signal readiness: during last month’s Army Day parade in Tehran, Iran displayed an S-300 launcher and radar vehicle. In military drills held in February, an S-300 system was observed firing a missile using what appeared to be an Iranian-made radar system—likely a substitute for imported systems rendered inoperable during previous strikes.

Iran’s heightened alert is driven not only by concerns over a possible US or joint US-Israeli strike but also by a growing fear in Tehran that Israel may act unilaterally. CNN reported on May 20 that US intelligence believes Israel is preparing for a potential strike on Iranian nuclear facilities.

In response, Iranian Foreign Minister Araghchi condemned the threat on May 22 and warned of “special measures” if it materializes. The same day, Iran’s UN mission submitted a letter holding Washington legally accountable for any Israeli military action. The IRGC-affiliated Tasnim News vowed severe retaliation, while Armed Forces Chief of Staff Mohammad Bagheri pointed to Iran’s April and October 2024 attacks on Israel as warnings of what could follow.

Janatan Sayeh is a research analyst at the Foundation for Defense of Democracies focused on Iranian domestic affairs and the Islamic Republic’s regional malign influence.