President Donald Trump warned Iran on Thursday it must make a deal over its nuclear program or "really bad things" will happen, and set a deadline of 10 to 15 days,

The head of the U.N. nuclear watchdog agency says Iran's enriched uranium "is still there," as he stresses the urgency of diplomacy to avert a U.S.-Iran war.

As the United States continues a significant military buildup in the Middle East, Iran has taken steps to signal its readiness for war, including fortifying its nuclear sites and rebuilding missile production facilities.

Trump said the world would know in 10 or 15 days whether Iran would reach a deal to avoid military action over its nuclear program.

The United States may launch a full-throttle attack on Iran as it continues to mobilise big weapons, including warships, jets, and others to surround Tehran.

Oil prices jumped Thursday to their highest level in nearly seven months and investors snapped up safe havens like gold, as tensions between the United States and Iran continue to flare.

The United States is building a major force of naval and air assets in the Middle East, potentially setting the stage for a sustained military campaign against Iran. The United States had two of the massive warships in the region in June last year when it targeted three Iranian nuclear sites during Israel's 12-day campaign of strikes on Iran.

Iran has issued a notam, alerting pilots and airlines not to hover in the area between ground level and FL100 as it is conducting rocket drills as it anticipates an attack by the United States.