The US State Department has moved to get tough on international companies engaged in Iran's energy sector, tightening economic sanctions imposed on Tehran over its nuclear programme.
Deputy Secretary of State James Steinberg said new sanctions would be imposed on a Swiss-based subsidiary of the National Iranian Oil Company that he described a key conduit for cash into the country's oil industry, and that other international companies would be investigated for their own Iran links.
"The international community should collectively abandon a business-as-usual approach to Iran," Mr Steinberg said in unveiling the first direct US moves against firms involved in Iran's energy sector since the passage of new sanctions in July.
He said four big global energy companies – France's Total, Norway's Statoil, Italy's ENI and Royal Dutch Shell – had already provided assurances that they had stopped or were stopping their Iran activities. But he said other companies were under investigation for possible sanctions breaches.
"We are engaging in conversations. We will sustain the confidentiality of those so long as we think it's productive," said Mr Steinberg. The US move seeks to tighten the screws on Tehran, which spurred the UN Security Council to impose new sanctions earlier this year that were supplemented by additional unilateral sanctions from the US, the EU and other major powers.