US President Donald Trump and Iran's senior officials have traded new threats of further action, after the two sides exchanged strikes.

Trump said Tehran had taken "too long to negotiate a deal" and would now "have to pay the price", without giving specific details. He said Iran had been "completely defeated" and was "all talk and no action".

It came after Iran's Foreign Minister Abbas Araghchi earlier warned his country would "leave no attack or threat unanswered", saying that the US had suffered "defeats on the battlefield".

The US said it struck Iranian sites on Tuesday in response to the downing of a US army helicopter in the Gulf. Iran then launched strikes at US bases in the region.

Iranian defence systems, ground control stations and radar sites were targeted near the Strait of Hormuz, the US military Central Command (Centcom) said.

Iran's Islamic Revolutionary Guard Corps (IRGC) said it launched strikes on 21 targets at US bases in the region, one in Bahrain and the other in Jordan, while Kuwait's army said it was also intercepting an attack.

Writing on his social media platform Truth Social on Wednesday, Trump said: "Iran's Military is a complete and total mess. Much of it, like their Navy and Air Force, doesn't even exist anymore - They have been completely defeated."

He added: "They've taken too long to negotiate a deal that would have been great for them, now they will have to pay the price!!!"

Trump's comments were in contrast to Tuesday, when he told journalists the US and Iran were "in the final throes of what will be a very, very good deal".

Also on Wednesday, Iran's foreign ministry spokesman Esmaeil Baqai accused the US of "damaging this diplomatic process through the contradictory messages it sends, its repeated shifts in positions and demands, and, worst of all, through repeated violations of the ceasefire".

He said Iran needed to re-assess the situation, adding that any diplomatic process required a minimum of stability.

On Tuesday, Centcom described its strikes on Iran as "a proportional response" for the Apache helicopter downing on Monday, with the IRGC describing them as "vicious".

Trump previously said on Truth Social that the helicopter had been "shot down" as it was patrolling the Strait of Hormuz, a critical shipping channel that has been effectively closed since the conflict started in late February.

Fox News quoted Trump on Wednesday as saying that an Iranian drone had hit the helicopter without exploding as it flew "very low" .

The two crew members survived and were rescued by an American sea drone.

According to US officials, Iran used a drone to launch the attack on the helicopter. But it is not clear whether the drone had deliberately attacked it, an unnamed US official told CBS News, the BBC's US partner.

The semi-official Iranian Mehr News Agency reported that Iran had not claimed responsibility for the downed aircraft.

The IRGC has said the latest US strikes targeted the cities of Jask and Sirik, as well as Qeshm island, and damaged a telecommunications tower and two water tanks.

Reuters cited a US official on Wednesday as saying nearly all of the Iranian missiles and drones launched at US bases in the Middle East in response were intercepted, with no reported casualties. (BBC)

Update news