Iran could step in to help address European energy security concerns once the doors to financial regimes open, the speaker of the Iranian parliament said.

Speaker Ali Larijani told visiting Bulgarian Prime Minister Boyko Borisov the Islamic republic could penetrate deeply into the European energy sector and help address some lingering security issues with the right conditions in place.

"Of course, under present conditions there are impediments on the way," Larijani said. "Banking relations with Europe are not yet fixed."

Sanctions pressures on Iran started easing in January after the United Nations confirmed compliance with a multilateral nuclear agreement brokered last year. European sanctions are easing faster than those enacted by the United States, though some sanctions that remain in place make it difficult to do business with Iran.

President Hassan Rouhani nevertheless toured Europe this year, returning with renewed commitments from energy companies eager to engage in a post-sanctions Iran.

Austrian energy company OMV was among the first to sign agreements with Iran in a step toward resuming formal operations in the oil-rich member of the Organization of Petroleum Exporting Countries.

Iran has offered its natural gas to a European market working to break Russia's hold over the energy sector. Russia supplies about a quarter of Europe's gas, though much of that runs through Ukraine, where regional conflicts have created risks to energy security.

Bulgaria in 2014 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. Last year, the government in Sofia said it was ready to help serve European energy needs.

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, canceled in 2013.