Nicosia, Nov 14, 2018 (AFP)

Rights group Amnesty International condemned Iran's execution on Wednesday of a gold trader and his accomplice as "abhorrent" and said it followed a "grossly unfair show trial".

Vahid Mazloomin and accomplice Mohammad Esmail Ghasemi were executed after being found guilty of "corruption on earth", Iran's most serious capital offence, the judiciary's Mizan website said.

Mazloomin had been dubbed the "Sultan of Coins" for allegedly exploiting a surge in gold demand from savers spooked by this year's currency crisis in Iran.

"With these abhorrent executions the Iranian authorities have flagrantly violated international law," said Amnesty's Middle East and North Africa research director, Philip Luther.

"These men were convicted after a grossly unfair show trial that was broadcast on state television," he said, adding that international law forbids the death penalty for non-lethal crimes.

Mazloomin and Ghasemi were found guilty in September and had their death sentences upheld by Iran's supreme court on October 21.

Iran has suffered a sharp economic downturn this year, fuelled largely by US President Donald Trump's decision in May to withdraw from a landmark 2015 nuclear deal and reimpose crippling unilateral sanctions on Tehran.

Fearing for the economy, many Iranians rushed to secure their savings by buying foreign exchange and precious metals.

The rush caused the rial to lose around 70 percent of its value against the dollar and the price of gold coins to quadruple at one stage this year.