The Wall Street Journal reported on Sept. 29 local time that the Houthis, once a ragtag guerrilla force, have recently pushed south from their established strongholds in western Yemen, seizing the strategic port city of Mocha and islands in the Red Sea to sharply expand their influence over the Bab el-Mandeb strait.
Reuters also reported that after capturing Mocha, the Houthis advanced to the Hanish Islands and Perim Island in the Bab el-Mandeb. The strait is a narrow waterway linking the Red Sea and the Gulf of Aden and a critical passage between Europe and Asia. Saudi Arabia recently restarted its East-West pipeline, which had been halted by drone attacks, and began loading crude at the Red Sea port of Yanbu, but concerns persist that the Houthis could resume attacks at any time.
The Houthis, who have about 350,000 fighters, prepared the offensive for months, according to the Journal. Since mid-last month they moved weapons and thousands of troops around Mocha to secure supply lines, while using their control over Yemen's telecommunications networks to intercept hostile communications and wage psychological warfare to sow confusion.
The group has no navy in the traditional sense but operates an asymmetric maritime force using coastal anti-ship missiles, suicide drones, mines, armed speedboats and unmanned surface vessels. Much of its ballistic and cruise missile, anti-ship and drone arsenal is based on Iranian technology. Houthi missiles have ranges exceeding 1,500 miles (2,400 kilometers), enough to strike all of Saudi Arabia as well as Israel.
The Quds Force, the elite arm of Iran's Revolutionary Guard Corps, has since around 2015 supplied the Houthis with components for assembling Iranian-style missiles and drones and dispatched technicians to build local production and modification capabilities, according to reports. The Houthis have used locally produced versions of Iran's Shahed-series suicide drones and the Samad drone, with a range of 1,500 kilometers, in attacks on Saudi Arabia, the United Arab Emirates and Israel.
Unusually for a non-state armed group, the Houthis have also used anti-ship ballistic missiles in combat. Their Iranian-made anti-ship ballistic missiles can reportedly detect and track targets using radar signals reflected off vessels.
More recently, Chinese dual-use goods have emerged as a new procurement channel. Citing United Nations reports and analysis by weapons experts, the Journal said "Chinese companies are supplying electronic components and drone-related equipment that can be used for both civilian and military purposes," adding that "China's share is growing particularly in the procurement of parts needed to build and upgrade drones."
That has prompted the observation that Iran created the Houthis but China grew them, with Chinese support becoming increasingly important during the group's recent expansion. This does not mean Beijing is directly supplying weapons to the Houthis, however.
The group's procurement network is also diversifying. The IRGC long smuggled small arms and drone and missile components into Yemen aboard traditional dhow sailing vessels, but U.S. forces and anti-Houthi factions inside Yemen have repeatedly intercepted the shipments. The Houthis are now using Djibouti, across the Red Sea, as a logistics transit point, and the U.N. has detected signs that the group is exchanging weapons and technology with al-Shabaab, al Qaeda's affiliate in Somalia. The U.N. has reported that al-Shabaab is in contact with the Houthis to obtain arms and expertise.
The Houthis' growing military strength is weighing on global energy markets as well as Middle East stability. Ships passing through the Bab el-Mandeb use the main route connecting Europe and Asia via the Suez Canal. The group's recent advance around the strait has heightened anxiety over international shipping and crude transport. The U.N. said the Houthis "are carrying out attacks in the Red Sea and advancing into the Bab el-Mandeb, threatening international trade and energy security."
