A growing number of empty supertankers have been turning away from the Persian Gulf as escalating Iranian attacks threaten a critical transfer hub for wartime oil shipments.

President Donald Trump’s deal for Russian diesel exposed the US to legal questions, opened a rift with his Republican allies and European leaders and heightened tensions with Ukraine — all in exchange for an outcome that experts suggest is unlikely to succeed.

Bulgaria summoned Russia’s ambassador to Sofia after two ships were hit off the country’s coast, as concerns mount over the security of Black Sea shipping.