The Houthi rebels lost Hodeidah airport on June 20, the latest in a long series of defeats and retreats inflicted during the Yemeni offensive. With UAE backing, the Yemeni military has marched 390 kilometres between Aden and Hodeidah, liberating the strategic Bab el-Mandab, and the winning battles at Dhubab, Mokha, Khokha, Al-Hays and Mafraq along the way. The Houthis showed some of their old tricks and some new ones in the failed defence of the Hodeidah airstrip. The fighting style used by the rebels has changed greatly since the period between 2004 and 2009. Then they fought the Yemeni government with rifles, machine-guns, rockets and the heaviest of their hardware was perhaps a few old tanks. <strong>____________</strong> <strong>Hodeidah offensive </strong> <strong><a href="https://www.thenational.ae/world/mena/houthi-retreat-leaves-yemeni-government-in-control-of-hodeidah-airport-1.742184">Houthi retreat leaves Yemeni government in control of Hodeidah airport</a></strong> <strong><a href="https://www.thenational.ae/world/mena/houthi-exit-from-hodeidah-non-negotiable-says-gargash-1.741601">Houthi exit from Hodeidah non-negotiable says Gargash</a></strong> <strong>____________</strong> Now they have the most advanced armour-piercing roadside bombs in the world, drones filled with explosives, long-range anti-tank guided missiles and even brand new medium-range ballistic missiles that regularly strike 900 kilometres out to Riyadh. How? The reason for this rapid advance since 2009 is resupply and training by Iran's Islamic Revolutionary Guard Corps (IRGC) and Lebanon's Hezbollah. Even the UN has presented <a href="http://www.un.org/en/ga/search/view_doc.asp?symbol=S/2018/68">conclusive evidence</a> regarding Iranian supply of ballistic missiles and international arms experts have traced <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwjG69eI_OLbAhUOr6QKHag1A-IQFgglMAA&url=http%3A%2F%2Fwww.conflictarm.com%2Fdownload-file%2F%3Freport_id%3D2550%26file_id%3D2564&usg=AOvVaw1H_Vi-r-AnnCdC6NA5mgca">drones</a> and <a href="https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0ahUKEwit_aH_--LbAhWrsaQKHbtpDOUQFgglMAA&url=http%3A%2F%2Fwww.conflictarm.com%2Fdownload-file%2F%3Freport_id%3D2598%26file_id%3D2600&usg=AOvVaw3-HIbR1Q45DRJQSm6uOdLL">other weapons</a> back to Iran. But the unsuccessful Houthi defence of Hodeidah airport also saw them use more sophisticated methods, some of which are very similar to the <a href="https://ctc.usma.edu/defeat-by-annihilation-mobility-and-attrition-in-the-islamic-states-defense-of-mosul/">tactics used by ISIS</a> in Mosul and other areas. Like ISIS, the Houthis have small numbers – probably under 2,500 in Hodeidah, a city of between 600,000 and 700,000 – but they must defend large areas and dominate large populations. How do they achieve this? Like ISIS, the Houthis use huge numbers of landmines to make up for their lack of numbers. Landmines – taken from Yemeni military stocks – and improvised explosive devices – which they build – are used to force attackers to slow down. Then the Houthis use snipers, long-range anti-tank guided missiles and mortars to cover these minefields, shooting at the troops as they move slowly through the mined area. The Houthis are also similarly placed to ISIS because they face the coalition’s air superiority, meaning that only the coalition have air assets and they have the most advanced strike aircraft and attack helicopters in the world, armed with very precise munitions. In an effort to negate the coalition’s air advantage, the Houthis have a number of counter measures. Like <a href="https://www.militarytimes.com/news/your-military/2016/10/01/tunnel-warfare-in-mosul-the-isis-fight-is-likely-to-go-underground/">ISIS in Mosul</a>, they go underground, digging trenches and covering them with boards and earth so that they can move from cover to cover without being seen from above. They also use civilians as human shields, placing their tanks next to houses and putting their sniper and missile teams into civilian houses where families may be sheltering. The Houthis also understand how to use the coalition’s strict rules of engagement against them. They use a weapon in one house or bunker, then walk to another bunker looking like a civilian, where a new weapon is located. This is exactly how ISIS exploited US adherence to the laws of armed conflict in Mosul. But the coalition has learned lessons from the US-backed fight against ISIS as well. Each Yemeni brigade has UAE-provided combat engineering vehicles for mine-clearing, and the coalition is getting better every day at spotting and disarming the hidden explosives. The coalition moves slow and steady, to save coalition and civilian lives. Pinpoint strikes from Apaches and aircraft are guided by Yemeni local agents and coalition drones, which allows the coalition to "multi-source", meaning to check the accuracy of the information with multiple information streams. Many valid military targets are not struck to eliminate the risk of killing a civilian. At the end of it all, a Yemeni soldier has to recapture ground and clear buildings. They are doing this and the advice coming from the coalition ensures they advance in a coordinated way, with coalition air support. The Houthis may have copied some ISIS tactics but it is worth remembering that the militant group lost control of every single city it defended and so too have the Houthis. The rebels can delay the recapture of Hodeidah but they are only delaying the inevitable. <em>Dr Michael Knights is a senior fellow at the Washington Institute for Near East Policy and has travelled to most of Yemen’s battlefronts during three trips this year.</em>