The US-Iran nuclear situation remains a focal point of global security concerns, with President Donald Trump having issued a warning to Iran’s Supreme Leader, Ayatollah Khamenei, demanding either a return to negotiations or the risk of war.

Expected talks between Iran and the United States would be a late, and perhaps last, opportunity to control Tehran’s nuclear ambitions and avoid war.

Iran's nuclear programme has been the subject of a long dispute between it and Western countries that fear it wants to build an atomic bomb, which Tehran denies. Here is a timeline of the dispute: 1957 - Iran and United States sign a nuclear cooperation deal and the United States delivers a research reactor to Iran a decade later.

Shortly before talks between Tehran and Washington on Iran's nuclear programme, the Iranian president has surprisingly left the door open to US investment in the country. "I see the Supreme Leader [Ayatollah Ali Khamenei] several times a week.

Weary from long years of biting sanctions and worried about U.S. threats of military action, Iranians have responded to the prospect of talks this weekend with expressions of hope that have boosted their stock market and depressed currency.

President Trump said that the United States would hold “direct” talks with Iran on Saturday in an effort to rein in the country’s nuclear program, saying Tehran would be “in great danger” if it failed to reach an accord.

Many Israelis were surprised when President Trump announced that the United States would engage in “direct” negotiations with Tehran in an effort to rein in its nuclear program.

U.S. President Donald Trump made a surprise announcement on Monday that the United States and Iran were poised to begin direct talks on Tehran's nuclear program, but Iran's foreign minister said the discussions in Oman would be indirect.

President Donald Trump on Monday said the situation with Iran is entering "dangerous territory" as he announced his administration would be talking to Iran on Saturday.