JAZAN, Saudi Arabia // The Saudi border guard points past a crumbling, abandoned village towards a road barely visible against the hazy backdrop of Yemen’s towering mountains.

“That is the Red Line,” he says.

Beyond it lies Yemen and the threat from its Houthi militia who have already killed three border guard troopers since a Saudi-led coalition began air strikes last month to stop a rebel advance on Yemen’s port city of Aden.

Hundreds of kilometres from the battle for the city, the border guard force — supported by Saudi artillery and army troops — have reinforced the kingdom’s frontier along the Houthi’s traditional north Yemen stronghold of Sadaa.

“We took control of all the high points,” the officer says atop the three-storey observation tower.

The post, named “Tayash”, was established one month ago. On the roof, two machine gunners aim their weapons out over the valley stretching for several kilometres towards Yemen’s scrubby mountains.

Since a 2009 incursion by the Houthis, Saudi Arabia has relocated villagers to modern housing compounds further from the border in a bid to improve security.

All that remains in the valley are abandoned clusters of roofless buildings and a distant mosque now devoid of worshippers.

So far, no shots have been fired in anger at this post, guards say.

“There are no Houthis” nearby.

To make sure, other guards scan the terrain with binoculars.

A noisy electricity generator powers their windblown base, which includes ground-floor sleeping quarters, about 100 kilometres from Saudi Arabia’s most southwestern city, Jazan.

Similar observation points and a communications tower can be seen on nearby hills.

Colonel Hasan Ageeli commands this sector of around 70 kilometres of frontier.

He is confident there will be no repeat of 2009, when Houthis occupied two small Saudi border villages — sending Saudi warplanes, artillery and special forces into action.

Col Ageeli said the kingdom is far-better prepared to face an incursion, with upgraded equipment and new observation posts offering a full overview of the buffer zone.

His men are also in high spirits, he said.

“They want to defend their country and feel proud,” Col Ageeli said.

The only Saudi casualties since a Riyadh-led coalition began air raids on Yemeni rebels two weeks ago have been the three border guards shot dead in separate incidents in the Asir region, adjacent to Jazan.

There have not been regular exchanges of fire even though some Houthi positions are only 100-150 metres from Saudi guards, Col Ageeli said.

A few minutes drive from the Tayash post, there were army artillery batteries and communication units, with about a dozen tanks and several armoured personnel carriers.

The front line is far enough away from Jazan city that most people there see no reason to worry.

“We are far from the border,” one resident of the Red Sea city said. “People are not afraid.”

But Abu Ibrahim, a taxi driver, isn’t so relaxed.

The coalition has not so far sent ground troops into Yemen. It says its aircraft have been destroying rebel missiles and other targets, but Mr Ibrahim fears the Houthis still a pose threat to his city.

“If there is a ground operation we worry the rebels might respond and hit the city with missiles,” he said. “But right now it’s peaceful.”

* Agence France-Presse