Iranian President Hassan Rouhani has dismissed new US sanctions on Supreme Leader Ali Khamenei as "outrageous".

In a speech broadcast live on Iranian state television, he said sanctions against Khamenei would fail because he has no assets abroad.

Rouhani said Tehran's "strategic patience" should not be mistaken for fear.

Meanwhile, US President Donald Trump has threatened to attack Iran in retaliation for any strikes by Tehran on anything American.