Iran has dropped Russia's Gazprom Neft from developing an oil field in the country, citing a lengthy delay in the project's implementation.

Senior oil ministry official Hamid Karimi said that a consortium of Iranian companies will replace the Russian firm in developing the Azar field, which sits near Iran's border with Iraq, AP reported quoting semiofficial Mehr news agency.

Iran - OPEC's second largest oil exporter and the world's fourth largest oil producer - relies on oil exports for about 80 percent of its public revenues.