US President Donald Trump grudgingly agreed not to reimpose nuclear sanctions on Iran on Friday, but officials warned that it would be the last time he issues such a waiver.

Instead, a senior White House official said, Trump wants Washington's European allies to use the 60 day period before sanctions relief again comes up for renewal to agree tougher measures.

At the same time as the renewed waiver was announced, the US Treasury imposed sanctions on 14 Iranian figures and companies, including the head of the country's judiciary, Sadegh Amoli Larijani.