Iran under renewed pressure: UN sanctions revive tensions, stall nuclear diplomacy

Diplomacy has taken a step back as threats and warnings have escalated between Western and regional powers and Iran, particularly following the reimposition of UN sanctions. With the nuclear negotiations reaching a deadlock, the three European parties to the 2015 nuclear agreement — the United Kingdom, France, and Germany — activated the “snapback” mechanism in response to Iran’s “continued nuclear escalation and lack of cooperation.”

Tehran suspended international inspections of its nuclear facilities after several of its nuclear sites and military bases were bombed by the United States and Israel in June 2025. Following the European troika’s decision to reimpose sanctions, Iran stood firm in its position, leaving no room for compromise or renewed negotiations. European nations, on the other hand, argued that Iran had failed to take the necessary measures to address their concerns, refusing to cooperate with the International Atomic Energy Agency (IAEA) and maintaining secrecy regarding its stockpile of highly enriched uranium (60%).

The Joint Comprehensive Plan of Action (JCPOA) places limits on uranium stockpiles and enrichment levels to prevent the programme from drifting toward nuclear weapons development. Iran, however, continues to insist officially that it has no intention of producing nuclear weapons, demanding guarantees against Israeli attacks on its nuclear facilities and refusing to hand over its enriched uranium in exchange for temporary sanctions relief.

Iran has often blamed the failure of the nuclear deal on the United States, which withdrew from the JCPOA during President Donald Trump’s first term and reinstated US sanctions. In response, Iran intensified its nuclear activities. Yet, there is no justification for Iran’s current high-level uranium enrichment, as it remains the only non-nuclear state enriching uranium to levels near the technical threshold for bomb production (90%), while the JCPOA had capped enrichment at 3.67%. According to IAEA estimates, before the US-Israeli strikes on four nuclear sites, Iran possessed roughly 440 kilograms of uranium enriched to 60%. If enriched to 90%, that amount would be sufficient to produce between 8 and 10 nuclear bombs.

The UN sanctions reimposed under the “snapback” mechanism include bans on conventional arms and uranium enrichment, restrictions on Iran’s ballistic missile program, travel bans and asset freezes targeting individuals and entities on the blacklist, and the confiscation of weapons or prohibited goods transported by Iran to state or non-state actors.

Amid these UN measures, prospects for negotiations and meaningful breakthroughs to limit Iran’s nuclear programme and stabilise the region appear increasingly dim. Tehran considers the renewed sanctions “illegal and unjust.” After the sanctions came into effect, Tehran recalled its ambassadors from France, Germany, and the UK for consultations. However, the European countries emphasised that the reimposition of UN sanctions does not mark “the end of diplomacy with Iran,” affirming that a lasting solution to the nuclear issue can only come through dialogue and negotiation.

The United States has expressed its readiness to hold direct talks, but Tehran seems unwilling to meet the US, Western, and regional conditions — chiefly, agreeing to direct negotiations, halting uranium enrichment, curbing its missile programme, and ceasing funding for its proxies in the Middle East. Efforts by Russia and China to push a UN Security Council resolution delaying the sanctions’ reimposition by six months failed, despite their attempts to support Iran through conventional arms and cooperation in missile and nuclear programmes. Nonetheless, they were unable to block the UN Iran Sanctions Committee’s decisions. Iran thus continues to rely on Moscow and Beijing for political support and economic and military cooperation, given its lack of strong alliances with major global powers.

The reinstatement of UN sanctions represents an effective means of pressuring Iran. Although the government claims it can withstand the pressure, the economy will inevitably suffer, increasing hardship for an already struggling Iranian society. Despite efforts to mitigate these challenges, Iran has endured severe economic and social crises in recent years.

While some hope the renewed sanctions will push Iran to allow IAEA inspectors to return to its nuclear sites and resume talks on its nuclear activities, it appears more likely that Tehran will further reduce cooperation with the IAEA. The Iranian parliament has passed legislation suspending cooperation with the agency and requiring approval from the Supreme National Security Council for any inspections — a move taken after the recent 12-day conflict.

Tehran may even consider withdrawing from the Nuclear Non-Proliferation Treaty (NPT). Yet, amid regional tensions and global power rivalries, Iran remains under heavy Israeli threats and fears further strikes on its territory. Diplomacy has entered a tense and uncertain phase, as Iran’s on-the-ground actions remain opaque in the absence of IAEA monitoring.

Iran still views its nuclear programme as a key source of national strength — a high-stakes strategy fraught with risk. Heightened US pressure could potentially drive a diplomatic resolution, as the reimposition of sanctions complicates Iranian policy and exacerbates economic strain.

In recent months, Washington has expanded its sanctions on Iran, targeting individuals and entities involved in networks that facilitate access to sensitive military goods, logistics for Iran’s armed forces, oil sales, technology transfers, and proxy funding.

Militarily, Iran has responded with heightened rhetoric, signalling its readiness by extending the range of its missiles to 2,000 kilometres and even hinting at withdrawal from the NPT — a move that would complicate verification efforts and intensify regional military tensions. In such an atmosphere of uncertainty, pragmatic diplomacy between Washington and Tehran could still emerge, though its prospects remain weak under the current escalation.

The return of UN sanctions will impact Iran’s oil industry, financial sector, shipping operations, and armed forces, while restricting maintenance and servicing of Iranian aircraft and ships. With Supreme Leader Ali Khamenei rejecting negotiations with the West, the likelihood of renewed confrontation has grown. The diplomatic door must remain open — otherwise, the region risks descending into greater turmoil. Israel may seize the opportunity for further military action against Iran, while Tehran, anticipating such strikes, could respond with indirect, non-military operations across the region.

Shaikha Obaid AlNuaimi is a Researcher at TRENDS Research & Advisory