Iran responded strongly to new United States sanctions yesterday, blaming Washington for shutting down diplomacy and lying about calls to discuss Teheran's nuclear weapons programme, as regional tensions escalated.

On Monday, US President Donald Trump had signed an executive order blacklisting Iran's Supreme Leader Ali Khamenei and top military chiefs. Sanctions on Foreign Minister Javad Zarif are expected later this week.

"At the same time as you call for negotiations, you seek to sanction the Foreign Minister? It is obvious that you are lying," Iranian President Hassan Rouhani said in a meeting with ministers.

The move to block Iran's leaders from access to international financial services comes just days after Iran shot down a US drone and Mr Trump called off a retaliatory air strike at the 11th hour.

The sanctions are not expected to affect Iran significantly as it already faces severe restrictions on oil exports, its most important source of income.