Meanwhile the US military said on Wednesday it launched a new round of strikes, marking a 12th successive night of American attacks.
The Yemen-based militants, who control areas near the Bab el-Mandeb Strait on the opposite end of the Arabian Peninsula from the Strait of Hormuz, said on Monday they were imposing a naval blockade on Saudi Arabia.
Even before the renewed threats to shipping traffic in the Red Sea, Iran's near-total blockade of the Strait of Hormuz had stoked inflation around the world, pushing up oil prices and squeezing US gasoline consumers.
Before the Red Sea flare-up, US President Donald Trump vowed on Wednesday to destroy an Iranian bridge or power plant every time Iran shoots at a ship in the Strait of Hormuz.
Iran's joint military command in turn warned that if Trump's threat against infrastructure was carried out, Iranian forces would target regional oil, gas, electricity and economic infrastructure and prevent the export of "even a single drop of oil".
