Iran will issue a preliminary list of international energy companies eligible to take part in tenders to develop its oil and gas fields within the next two weeks, a senior Iranian oil official said on Monday.

"Not all foreign companies active in the oil industry can participate in Iran's tenders," Ali Kardor, managing director of the National Iranian Oil Company (NIOC), was quoted as saying by the oil ministry's news agency Shana on Monday.

"Only those international companies that meet the standards of NIOC will be chosen."

Kardor said that, apart from U.S. companies, there were only around 37 companies in the world that might meet Iran's standards.

He said companies would only be eligible that are registered as exploration and production or international oil companies and are also rated by Standard & Poor's, Moody's or Fitch credit rating agencies.

"After creating the first list of international companies, a limited tender will be held," Kardor added.

The tenders will be based on Iran's new oil and gas contracts (IPCs) which have yet to be unveiled after some amendments.

Iran has promised IPCs will offer more flexible terms and end a system known as buy-back contracts that foreign companies say give them a limited return on investment while denying them any rights to the oil, with the Iranian government taking the bulk of the profits.

However Kardor reiterated on Monday that alongside IPCs, oil fields could still be developed through buy-backs, engineering, procurement, and construction and engineering, procurement, construction and financing contracts. – Reuters