The possible withdrawal of French oil major Total from Iran's South Pars gas field has not slowed down the project, a senior Iranian official said, adding that Tehran is in talks with Russia’s Gazprom over the development of two other fields.

President Trump said in May that the United States would impose new sanctions against Iran, a major oil and gas producer, after abandoning a 2015 agreement with Tehran.

Total said that it would pull out of the multi-billion dollar South Pars project if it did not receive a waiver from the United States to protect it from sanctions that Washington might impose on companies doing business with Iran.

"This claim that the development of phase II of the South Pars field has been stopped because of Total is not correct and everything is going according to plan," Gholamreza Manouchehri, deputy head of the National Iranian Oil Company, was quoted as saying by state news agency IRNA on June 19.

Manouchehri said if Total walks away from the South Pars field, Chinese state-owned energy major CNPC, which already holds a 30% stake in the field, will take over.

He said if both leave, PetroPars, a subsidiary of the national oil company, is prepared to step in.

Manouchehri also said Iran was in talks with Russia's Gazprom over the development of the Azar and Changuleh oilfields.

He added that Iran plans to increase the production potential of its oilfields by 400,000 bbl/d.

"By implementation of 34 projects in different fields, more than 400,000 bbl/d will be added to production potential of the Iranian oilfields," Manouchehri said, noting that the value of the projects was more than $6 billion.

The U.S. sanctions on Iran’s petroleum industry will take effect after a 180-day "wind-down period" ending on Nov. 4, but many European refiners, as well as buyers in Asia, are already curbing their Iranian oil purchases.