Donald Trump has issued his most direct military threat yet against Iran, warning that the United States is prepared to strike a deeply buried, heavily fortified underground nuclear facility if Tehran does not agree to a new agreement on its nuclear programme. The warning came as diplomatic back-channels between Washington and Tehran remain fragile, and as Iran continues to enrich uranium at levels that Western governments describe as dangerously close to weapons-grade. The facility in question is Fordow, a uranium enrichment plant built inside a mountain near the city of Qom in northern Iran. It was constructed specifically to survive conventional air strikes, and military analysts have long said that only the most powerful bunker-busting munitions — including the US military's Massive Ordnance Penetrator — could reach it.

Trump's statement signals that Washington is willing to use exactly those weapons if talks collapse. Iran's leadership has responded with defiance. Senior officials in Tehran have insisted that their nuclear activities are entirely peaceful and that they will not negotiate under what they call "a policy of maximum pressure." The standoff is being watched closely across the Middle East and in Europe, where governments fear that a military strike could trigger a wider regional conflict.

Russia and China, both of which have economic ties with Tehran, have called on all sides to return to diplomacy. The confrontation puts the entire framework of nuclear non-proliferation under new strain.