Fleeing to Caves and Training Underground: An Investigation into the Secret Military Bases of the Houthis

Defense Line Special - Investigation Unit

| The Houthi leader orders the construction of thousands of shelters and fortified rooms, fearing the fate of Hezbollah leaders and criticizing the construction of tall buildings.

In an underground hideout in the rugged mountain ranges of northern Yemen, the leader of the Houthi group spoke about shelters, fortified rooms, and underground bunkers as one of the key elements of self-defense, expressing admiration for Israel's focus on building shelters and fortified rooms to protect itself while targeting "our peoples." He also expressed strong disapproval of Arab countries focusing on constructing high-rise towers and large buildings, which, according to him, could be destroyed by "three or four bombs" that would kill all the inhabitants.

Abdul-Malik al-Houthi, in his weekly pre-recorded speech, which he regularly uses to address the group's members and supporters, as well as citizens forcibly gathered each Thursday to listen to "the speech of the leader," is clearly expressing his concern about the killing of Hezbollah's leader, Iran's proxy in the southern suburbs of Lebanon, and the deaths of senior party leaders in Israeli attacks on their leadership compounds, and the collapse of Tehran's allies in Syria.

He cannot hide the deep fear that is consuming him and his group, along with his fear of suffering the same fate as Hassan Nasrallah, who was his mentor and reference. He is clearly urging his group to focus more on investments and efforts to develop underground military infrastructure, which the group considers a top priority in its combat doctrine and its long wars as an armed insurgency movement based on guerrilla tactics, mountain warfare, and taking refuge in fortified mountains.

The fragile UN truce provided the Houthis with a golden opportunity to focus on developing their military capabilities and building fortified facilities, digging tunnels and caves in the mountainous areas under their control, to provide safe havens for the group's leadership and activities, storing weapons, and securing manufacturing centers for war materials and missile and drone assembly workshops. These activities reflect the group's preparations for prolonged wars and anticipation of possible attacks against them.

The Houthis benefit from their accumulated experience as an armed insurgent movement relying on guerrilla tactics and mountain warfare, alongside mimicking the methods of Iran and its affiliated groups. Experts from the Iranian Revolutionary Guard and Hezbollah have contributed to securing Houthi fortifications.

For the past year, the group has focused its efforts on rebuilding its forces, bunkers for its leaders, and conducting comprehensive updates to its security systems, precautions, deployment tactics, and operational command centers, in an effort to escape from U.S. and British airstrikes, as well as Israeli attacks targeting the group since last January. This comes in response to the group's attacks on commercial ships and military equipment in the Red Sea, the Gulf of Aden, and the Arabian Sea, under the banner of supporting Gaza and Al-Aqsa.

Before this, the group had managed to build fortified underground facilities beneath the mountains in rugged areas to avoid airstrikes by "Operation Decisive Storm" and "Restoration of Hope," launched by the Saudi-led Arab coalition supporting the Yemeni government in March 2015. The group successfully hid some of the weapons and strategic ammunition it seized from Yemeni army stocks, along with advanced technologies and components flowing in from Iran.

The continued flow of war technologies through maritime and land smuggling routes helped the Houthis develop their missile capabilities, air defense systems, and drones.

The Houthis benefit from their accumulated experience as an armed insurgent movement focused on guerrilla warfare and mountain fighting, alongside copying the methods of Iran and its affiliated groups. Experts from the Iranian Revolutionary Guard and Hezbollah have helped fortify Houthi positions.

The group has distributed military bases across the areas it controls, with a focus on Saada governorate, the surrounding mountainous provinces of Amran and Hajjah, the capital Sana’a and its surrounding highlands, as well as the coastal governorate of Hudaydah, and the western mountains overlooking the Red Sea.

Bases and Shelters in the Northern Mountains

Satellite images and Google Earth show that the group has established dozens of pr
imary and secondary bases in the mountains of Saada and the adjacent mountain range in Amran, Hajjah, and Al-Jawf, digging caves to store weapons, equipment, fuel, money, launching platforms, and shelters for drones, air defense systems, and foreign advisors.

The results of the analysis conducted by the "Defense Line" team reveal extensive construction activities in Saada city and its surrounding districts of Al-Safra, Sahar, Haydan, Saghine, Al-Buqaa, and Kitaf.

These strategically important areas have been targeted by numerous American and British airstrikes.

Some of the U.S. stealth bomber raids targeting underground facilities on October 17 hit two Houthi bases in Saada.

In Al-Jawf governorate, images from Google Earth and open-source intelligence sources analyzed by the "Defense Line" team show ongoing Houthi military installations in the mountainous areas, particularly in the mountain chains in Al-Zahir and Al-Humaydah districts, adjacent to Harf Sufyan in Amran, and Khurab Al-Marashi district connecting Al-Jawf with Amran and Saada. Another area of significant Houthi activity is the mountainous district of Rajouza, extending to the border district of Al-Bart Al-Aan in Saada, which contains the highest mountains in Al-Jawf and is crucial for the Houthis due to its proximity to Saada and its rugged terrain.

These mountain ranges were targeted by American and British airstrikes in recent months.

In Hajjah governorate, Houthi military installations are concentrated in the western districts of Abs, Midi, and Haran, overlooking the Red Sea, extending to the border with Saudi Arabia in the Hara district.

Satellite images and intelligence reports reveal the Houthi focus on constructing underground military bases, tunnels, and shelters in the coastal areas of Abs, Midi, and Haran, including ballistic missile shelters, drone storage, and radar systems. There are also workshops for assembling and manufacturing military equipment, mines, and explosive boats.

In Amran governorate, satellite images and intelligence sources point to new Houthi installations in the mountainous areas, especially in Harf Sufyan, which is strategically important as the southern gateway to Saada. This area, located on the borders of Al-Jawf and Hajjah, has old military bases and important roads connecting Sana’a, Amran, Saada, and Al-Jawf.

A previous investigation by the "Defense Line" team revealed a new Houthi base in the "Al-Hira" area west of Harf Sufyan city, which is one of the main missile and drone bases.

This base, built by the Houthis after 2022, was targeted by American and British airstrikes in November.

Sana'a, a Weapons Storage and Caves Network

In the capital Sana’a and its surrounding mountainous highlands, which belong to Sana’a governorate, there are the second-largest Houthi military bases. The Houthis continue to establish new underground bases, tunnels, and fortifications beneath the mountains surrounding the capital, while also updating older concrete-buried military structures from the era of Ali Abdullah Saleh.

The group takes advantage of the terrain and military infrastructure, using military installations and weapon depots seized from the Yemeni army during their campaigns and sectarian recruitment efforts inside and outside Yemen's borders.

Satellite images and open-source intelligence reveal that the group has rehabilitated old underground weapon depots in the Al-Hafa camp and the mountains of Naqam east of the capital, and created new, larger shelters and fortifications in the Naqam mountain range.

Security sources previously reported that the Houthis had conducted extensive digging in the eastern mountains of Sana’a to search for old weapon depots and build new fortifications and tunnels.

Satellite images also show the Houthis building extensive installations and opening new roads in military sites such as Jirban north of the capital and the Dhal'a Hamdan area to the northwest, where multiple old and new camps and extensive caves used for military operations exist.

Al-Bayda and Marib

To the east, the Houthis have established military facilities in Al-Bayda governorate, deploying missile launch platforms and drones towards the Arabian Sea.

Intelligence sources and satellite images also reveal the group's continued construction of tunnels, fortifications, and new roads in the strategic Hailan mountain range in Marib, along with tunnels and fortifications along the frontlines.

Militarization of Hudaydah and Western Highlands

In Hudaydah governorate, the western coast overlooking the Red Sea, the Houthi group has directed significant efforts to build new military facilities in the Tihama plains, islands, and ports in Hudaydah city and Salif.

The group has created an extensive network of underground tunnels and caves, similar to those used by Hamas and Hezbollah in Gaza and the southern suburbs of Beirut. They have developed secure shelters for storing advanced maritime weapons, mines, and boats, along with workshops for assembling surface-to-sea and air-to-ground missiles, and systems for radar and air defense.

A previous investigation by the "Defense Line" team revealed that the Houthis have been digging shelters and tunnels inside the Hudaydah airport and its airbase, attempting to rehabilitate the runway for military operations.

Security sources also revealed that the Houthis had dug tunnels in the eastern mountain ranges of Hudaydah city to store deadly weapons and build underground shelters.

Satellite images show the creation of new military facilities and road openings in the western mountains of the
governorates of Raymah, Dhamar, Ibb,