US President Donald Trump has threatened military action against Iran -- in the wake of its deadly crackdown on protests -- if Tehran fails to agree a deal to restrict its controversial nuclear programme.

Iranian officials have repeatedly threatened immediate retaliation if there is an attack, pointing to American military bases in the Gulf as potential targets.

With talks between Iranian Foreign Minister Abbas Araghchi and US envoy Steve Witkoff expected this week but not confirmed, Iran's Fars news agency, seen as close to the security forces, has for two days in a row published images of US bases in the region.

The images carry no comment and only the day of the week and the date according to the Persian calendar.

The picture for Tuesday showed an aerial view of the Al Dhafra air base outside Abu Dhabi, which is used by US and French forces.

On Wednesday, meanwhile, Fars showed the Isa Air Base in US ally Bahrein where US planes have also deployed.

But images aroused concern in France due to its troops stationed in the UAE and President Emmanuel Macron said on Tuesday that Paris was watching the situation closely.

"We are obviously very vigilant regarding this situation," Macron said.

"We have taken all necessary measures to ensure that our soldiers there are deployed in optimal security conditions," he added.

On Tuesday, a US fighter jet shot down an Iranian drone that approached American aircraft carrier the USS Abraham Lincoln which deployed to the the Middle East last month as the US steps up pressure from Tehran.

However there was no immediate suggestion the images published by Fars represented fresh intelligence.

AFP has confirmed the images of the Isa air base are old. Also, according to satellite images reviewed by AFP, as of February 3 there was no massive deployment of aircraft at the base of Al Dhafra.

With tensions still not abating, a new billboard appeared in Tehran showing American planes crashed into a hillside with Iranians flying the flag of the Islamic republic above.