Kharg Island is a small rocky outcrop just 15 nautical miles (24km) off the coast of Iran. Very large tankers - capable of carrying up to 85 million gallons of oil - are able to come up to the island's long jetties to pick up the oil. Centcom said US forces had struck "more than 90 Iranian military targets on Kharg Island, while preserving the oil infrastructure". "He's showing it as being merciful but saying he could be more punishing to the IRGC" by targeting the oil facilities, Crump, who is also CEO of intelligence consultancy Sibylline, told BBC Radio 4's Today programme. "That doesn't really say much for their [the Iranian people's] future," he said, adding that, when the island's oil infrastructure was destroyed during the Iran-Iraq war in the 1980s, it took a long time to rebuild. US media reports that amphibious ships carrying up to 5,000 Marines and sailors are now being sent to the Gulf, adding to that speculation.