A consortium managing a pipeline designed as way to diversify the European natural gas sector said it hasn't made any contacts with potential Iranian suppliers.

Iran may receive staged sanctions relief as a result of the breakthrough nuclear agreement brokered with the five permanent members of the U.N. Security Council and Germany. Energy companies BP and Shell both confirmed in response to emailed questions they were reviewing potential work in an Iranian oil sector that could be opening up to investors.

When reviewing the credentials of Bulgarian Ambassador to Tehran Christo Polendakov in May, Iranian President Hassan Rouhani said his government viewed Bulgaria as a means to tap into the European energy market.

Bulgaria last year suspended its role in a now-shelved Russian natural gas pipeline planned for Europe, South Stream, arguing it violated legal requirements in the European Commission that restrict the role of gas suppliers from distribution projects. In January, the government in Sofia said it was ready to help serve European energy needs.

Bulgaria could play a role in the Trans-Adriatic pipeline meant to ferry gas from Azerbaijan to Europe through its existing pipeline infrastructure. Lisa Givert, head of communications for the TAP pipeline consortium, said in response to email questions there's been no contact with Iran since the nuclear deal was brokered.

"TAP has not made any contact or made any offers to Iranian shareholders to join the TAP project," she said.

Iran in the past has held out its vast natural gas reserves as an option to help the European economy break the Russian grip on its energy sector. The Islamic republic said its gas would be a necessary component of the Nabucco pipeline, cancelled in 2013.

Gas links through Bulgaria, and pipelines stemming from the Shah Deniz project in Azerbaijan, are among the projects included in the European energy diversification strategy. British energy company BP has awarded more than $1 billion in development contracts since selecting TAP as its option for Azeri gas in 2013.

"TAP is fully committed to transport Shah Deniz [gas] volumes from the Caspian through Greece, Albania and into Italy," the spokeswoman said.