Iran's President Hassan Rouhani has said the latest US sanctions against the country demonstrate Washington's "desperation" and will not succeed.
President Trump signed further measures aimed specifically at Iran's supreme leader Ayatollah Khamenei on Monday.
The new sanctions came after Tehran downed a US drone last week claiming it was flying over Iranian territory.
Iran's Foreign Ministry earlier said the latest US sanctions meant "closing the channel of diplomacy forever".
But speaking in Jersualem this morning, the US National Security Adviser John Bolton emphasised that dialogue with Iran was still possible.
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