The Yemen-based group, the Houthis, have been making headlines after a number of attacks on Saudi Arabia.

12 people have died after an attack on the King Khalid International Airport in Riyadh, Saudi Arabia.

While no group has taken responsibility for the attack, the Houthis have shared a warning to aviation firms and passengers advising them against using Saudi airports and airspace.

Sky News Middle East Correspondent Adam Parsons spoke to The Pat Kenny Show about the probabilities of it being the group behind Saturday's attack, but for those who are unfamiliar with the group, here's what you need to know.

Who are the Houthis?

The Houthis are an armed political and Shia Muslim religious group from northern Yemen who are backed by Iran.

They have aligned themselves with the "axis of resistance", which is led by Iran, against Israel, the US and the wider West.

Other groups who have also aligned with this "resistance" include Hamas and Hezbollah.

The group emerged in the 1990s and their aim is to topple the internationally-supported government of Yemen.

Over the years, the Houthis have gained control of somewhere between 25%-33% of Yemen's territory.

Why are the Houthis attacking Saudi Arabia?

The Houthis are supported by Iran, who is a longtime rival of Saudi Arabia. Saudia Arabia doesn't want the Houthis to take over Yemen, as they fear it will make it an Iranian satellite state.

Over the years, Saudi Arabia and the Houthis have been sending air strikes and drones back and forth, and the fighting has led to a humanitarian crisis in Yemen.

In addition, there is a fear that if the Houthis take control of the Red Sea coast, this could affect shipping going up the Suez Canal which is currently being used by Saudi Arabia to transport their oil instead of using the Strait of Hormuz.

Mr Parsons explained: "If the Houthis completely exert control on the Red Sea coast, that means they take control of the Bab al-Mandab Strait, and that affects shipping going up through the Suez Canal.

"At the moment, the Saudis are putting their oil, or a great deal of it, through the Suez Canal rather than through the Strait of Hormuz. And the upshot of all of that is that potentially the price of oil goes up."

Main image: Houthis Drone Attacks On Saudi Arabia Oil Plants Pic: Video Grab, Saudi Arabia, 14/09/2019.