What are key issues dividing US and Iran in nuclear talks?

Feb 5 (Reuters) - The United States and Iran are due to hold crucial talks in Oman on Friday, with President Donald Trump's threat of military action looming over a region buffeted by conflict since 2023.

Washington wants the talks to include Iran's nuclear programme, its ballistic missiles, support for armed groups around the region, and its "treatment of their own people", U.S. Secretary of State Marco Rubio said on Wednesday.

Iran says it will only discuss its nuclear programme.

Here's a primer on the issues:

NUCLEAR PROGRAMME

This has been a focal point of tensions since 2003, when the International Atomic Energy Agency (IAEA) reported that Iran had not complied with the Nuclear Nonproliferation Treaty (NPT), after revelations it had carried out secret nuclear work.

The NPT gives Iran the right to a civilian nuclear energy programme but bars it from using the technology - particularly uranium enrichment - to develop atomic weapons.

Western powers deployed a mix of sanctions and diplomacy to try to curb Iran's programme, fearing Tehran sought an atomic bomb, despite its denials.

In 2015, Western powers along with China and Russia struck a deal with Iran which tightly restrict its nuclear work and loosened sanctions. It was a prominent foreign policy achievement for then U.S. President Barack Obama.

However, President Donald Trump abandoned it in his first term, calling it the "worst deal ever".

Under former President Joe Biden, indirect talks resumed, but with little progress. Iran began enriching uranium at 60% fissile purity - not far from the 90% needed for a bomb.

In 2025, Trump returned to the White House, saying Iran must agree to a nuclear deal or "there will be bombing". Several rounds of talks failed to produce a deal.

In June, Israel launched strikes, saying the aim was to prevent Iran from building nuclear weapons. The United States joined the campaign on June 22, bombing Iranian nuclear sites before brokering a ceasefire.

The status of the facilities damaged in last year's bombing remains unclear.

MISSILES

Iran has one of the Middle East's biggest stockpiles of ballistic missiles.

It fired missiles directly at Israel for the first time in 2024 in retaliation for an Israeli attack on its Damascus embassy compound, as conflict spread through the region after Hamas' October 7 attacks on Israel.

In last year's war, Iran fired hundreds of missiles at Israel, killing dozens of people and testing Israel's multi-layered air defences.

Iranian Foreign Minister Abbas Araqchi said on January 30 that "Iran's defensive and missile capabilities — and Iran's missiles — will never be the subject of any negotiations".

Rubio said on Wednesday meaningful talks must include "the range of their ballistic missiles".

Israel has likened the danger of Iran's missiles to its nuclear programme. Prime Minister Benjamin Netanyahu said in January that Iran's "attempt to build atomic weapons" and "20,000 ballistic missiles" were like "two lumps of cancer".

REGIONAL ALLIES

Iran long projected influence around the region by supporting armed groups including Hamas and Lebanon's Hezbollah.

Known collectively as the "Axis of Resistance", these groups had grown into a potent challenge to Israel on the eve of the October 7 attacks.

Israel dealt major blows to Hezbollah and Hamas in conflicts that followed. Tehran's regional sway was further weakened by the ouster of its Syrian ally, Bashar al-Assad.

Despite their weakened positions, neither Hamas nor Hezbollah have yielded to demands for their disarmament.

Washington is also seeking to counter the role of Iran-backed militias in Iraq. Reuters reported that Washington has threatened senior Iraqi politicians with sanctions targeting the Iraqi state - including potentially its critical oil revenues - should Iran-backed groups be included in its next government.

The Iran-aligned Houthis of Yemen, who fired missiles at Red Sea shipping and Israel during the Gaza war, remain firmly in control of Yemen's most populous areas.

IRANIAN PROTESTERS

Trump stepped up his threats of military action against Iran during a wave of protests that erupted in December over economic hardship before swelling into widespread demonstrations demanding an end to clerical rule. It was Iran's deadliest unrest since the 1979 revolution, with thousands killed.

As Iran cracked down, accusing foreign enemies of fomenting the unrest, Trump warned Tehran against shooting protesters and vowed to "take very strong action" if Iran executed protesters. He later said Tehran had called off mass hangings.

Writing by Tom Perry, Editing by William Maclean