The US Treasury Department announced Wednesday that it imposed sanctions on a global network of individuals and entities that used front companies to facilitate the sale and delivery of Iranian oil.

Two Iranian-based companies purchased and exported petrochemical products from numerous US-sanctioned Iranian firms worth hundreds of millions of dollars to companies throughout East Asia, it said in a statement.

Petroleum products were sold to another Iranian-based company for onward shipment to China by "the use of front bank accounts and companies in order to obfuscate the shipment and sale of Iranian origin petrochemicals," it said.

At least half a dozen additional firms acted as front companies by disguising their roles to evade US sanctions by materially assisting or providing financial or technological support, according to the agency.

Two United Arab Emirates-based Iranian individuals also had a role to export Iranian crude oil and petrochemical products on behalf of a Switzerland-based firm, it added.