The United States on Wednesday imposed sanctions on Iranian Foreign Minister Mohammad Javad Zarif, the US Treasury Department’s Office of Foreign Assets Control said on its website.

The Treasury Department said it was imposing sanctions on Zarif for acting on behalf of Iranian Ayatollah Ali Khamenei.

“Javad Zarif implements the reckless agenda of Iran’s Supreme Leader, and is the regime’s primary spokesperson around the world,” Treasury Secretary Steven Mnuchin said in a statement.

Tensions have risen between the United States and Iran following US President Donald Trump’s withdrawal last year from a 2015 international nuclear accord with Tehran. Sanctions reimposed on Iran have led to more talk of open revolution in the autocratic dictatorship as citizens desire more freedom – both economically and personally. The United States remains very popular with young Iranians who see it as a possible partner under President Trump.

Fears of a direct US-Iranian conflict have risen since May with several attacks on oil tankers in the Gulf, Iran‘s downing of a US surveillance drone, and a plan for US air strikes on Iran last month that Trump called off at the last minute.

Foreign Minister Mohammad Javad Zarif is believed to be a multi-millionaire with overseas accounts in numerous countries.