Bab al-Mandab has been fought over for weeks. On October 5, a spokesman for the Yemeni army announced that government forces had retaken control of the Bab al-Mandab Strait in a large-scale operation, as JFeed reported. That came a month after a surprise Houthi offensive on southern port cities gave the group control of the waterway.
The Saudi-led coalition launched its "Dawn of Yemen" air campaign on the same day. It sent 100 warplanes against at least 324 Houthi targets and provided air defense over the strait. Yemeni forces, including the Giants Brigades, reported advances at the time.
On October 17, The Wall Street Journal reported that officers of Iran's Islamic Revolutionary Guard Corps (IRGC) were on the ground in Yemen directing Houthi operations. According to that report, the officers were helping the Houthis take territory along the Bab al-Mandab coastline. They were also supplying targeting intelligence for strikes on Saudi Arabia.
Trump's remark about Israel's help to Riyadh came the day before that report, when he spoke to reporters at the White House.