While many "western" media missed it, we reported that one brigade of regular United Arab Emirate troops invaded Yemen through the port of Aden. Videos from Yemen show large columns of French build Leclerc tanks and other modern UAE equipment. The Saudi and UAE spokesperson declared that they only brought equipment for Yemenis but that can not be true. The tanks will certainly be operated by people with the necessary extensive training on these expensive high tech vehicles, not with fresh off the street recruits with a few weeks of basic training.
After taking Aden the UAE military, some Yemeni infantry forces trained over the last months outside the country and some local southern separatist groups moved north and attacked the Al Anad airbase held by the Houthi militia and parts of the Yemeni army loyal to former president Saleh. After only a few short skirmishes the Houthi retreated and the UAE troops moved into the base. They then moved further north towards Taiz.
But the UAE military is not the only force invading Yemen.
With again few mentions in the media a Saudi brigade invaded Yemen from the north and moved from Sharoah in Saudi Arabia to AlAbr District and from there west towards Marib:
"Dozens of tanks, armoured vehicles and personnel carriers, as well as hundreds of Yemeni soldiers trained in Saudi Arabia, arrived in Yemen overnight" via the Wadia border post in the north of the country, a Yemeni military source told AFP.
I guestimate that the Saudi unit is likely to be about the same size as the UAE one. Each has about one regular mechanized brigade of some 3,000 to 4,000 troops with several battalions of freshly trained Yemeni infantry troops and local mercenaries attached to it.
The strategic target of this two-pronged attack is the capitol Sanaa currently held by the Houthi. They are to be pushed back north into their home province Sadah.
For the invading force the easy part is over. This will now be literally an uphill battle. The capitol and the approaches the Saudi and UAE military will have to take are mountainous. The roads there are easy to block and in such confined space, as the Israelis learned in Lebanon 2006, huge main battle tanks are simply sitting ducks to be killed by small anti-tank teams.
There is also an unknown factor in the form of AlQaeda in the Arab Peninsula which rules disguised as "Sons of Hadramaut" that eastern province and the harbor city Mukalla. AQAP just expressed its comfort with Yemeni culture and religion by blowing up a 700 year old mosque in the area.
Some months ago AQAP received weapons from Saudi Arabia to hold up the Houthis but its loyalty towards the Saudis and UAE is very dubious. There are confirmed reports that AQAP has taken over some towns near to Aden and now rumors that AQAP has a presence in Aden and wants to take that big harbor city. Will the UAE troops be comfortable with an uncontrollable AQAP sitting right on their main supply line?
The Wadia border station the Saudis used to cross into Yemen is also not safe. About a year ago two Saudi soldiers were killed there when some AQAP types attacked from Yemen.
There are also Islamic State forces in Yemen and an ISIS aligned group in Saudi Arabia took credit for yesterday's suicide bombing which killed some 17 Saudi security personal in Abha near the border with Yemen.
The troops invading Yemen will not only have to watch out for Houthi traps and ambushes when they move up into the mountains towards Sanaa. They will also have to intensively watch their backs. Has the "young general", as the Saudi Minister of Defense is mocked now, any idea of the cauldron his troops are getting into?