The chief executive of French oil and gas major Total has said that US sanctions on Iran represent a huge challenge. Patrick Pouyanne told reporters in the Russian city of St. Petersburg that he held little hope of receiving a waiver from the US to keep investing in an Iranian gas project. Also speaking in St. Petersburg, Igor Sechin, chief executive of Russia’s Rosneft, said that the US decision to quit the 2015 nuclear deal with Iran could affect 5 percent of global oil production. As for the new president of the Petroleum Association of Japan (PAJ), Takashi Tsukioka, he said Japanese oil refiners will likely take a few months to decide policy on Iranian crude purchases in response to the US sanctions. Japanese refiners are gathering information and have not yet held talks with the Japanese or US government, said Tsukioka, who is also chairman of Japan’s second-biggest refiner, Idemitsu Kosan Co. Policy on import curbs will likely be decided over the next few months after taking into account the responses of other users of oil, including China, India, South Korea, France and Italy, he said. Given a 180-day wind-down period for buyers of Iranian crude to cut their purchases, the refiners will likely have to decide by August on the curbs, he added.