A court in Iran has sentenced billionaire businessman Babak Zanjani and two accomplices to death for embezzlement, the country's judiciary said on Sunday, in a case widely watched due to the tycoon's prominent role in helping the Iranian government evade oil sanctions during the rule of former President Mahmoud Ahmadinejad.

Iran's Islamic court convicted the defendants of "spreading corruption on earth," a capital offense, and ordered them to repay funds embezzled from, among others, state-run National Iranian Oil Company (NIOC), judiciary spokesman Gholamhossein Mohseni Ejei said during a live television broadcast.

Zanjani and his two co-defendants can appeal against the ruling. A news website run by Iran's judiciary identified the others as Mahdi Shams, a British-Iranian businessman who was detained in 2015, and Hamid Fallah Heravi, a retired businessman, according to the Associated Press.

"The court of first instance… sentenced the three defendants to death," Ejei said in a weekly news conference. The three were also ordered to pay a fine equivalent to a quarter of the sums they had laundered, he said.

By his own account, Zanjani for years arranged billions of dollars of oil deals through a network of companies stretching from Turkey to Malaysia and the United Arab Emirates. Zanjani amassed a fortune of $10 billion, along with debts of a similar scale, the tycoon once told an Iranian magazine. The AP reported that Zanjani's fortune is worth an estimated $14 billion.

At the time of his arrest in December 2013, a judicial spokesman said "he received funds from certain bodies… and received oil and other shipments and now has not returned the funds". Prosecutors accused him of owing the government more than $2.7 billion for oil sold on behalf of the oil ministry.

Iran emerged from years of economic isolation in January when world powers led by the United States and the European Union lifted crippling sanctions against Tehran in return for curbs on Tehran's nuclear ambitions.