Air travel in the Saudi Arabian capital of Riyadh has been virtually paralyzed following a major airport attack by Yemen's Iran-backed Houthi rebels that resulted in massive casualties, prompting authorities to extend the airport's closure.

According to Reuters on the 12th (local time), Saudi Arabia's General Authority of Civil Aviation (GACA) announced that it is extending the suspension of operations at King Khalid International Airport in Riyadh in the wake of the Houthi rebel attacks over the weekend.

The civil aviation authority explained, "This is a measure to thoroughly inspect the safety of airport facilities and their operational readiness."

King Khalid Airport is Saudi Arabia's second-busiest key airport, following Jeddah Airport.

The airport was completely shut down immediately after a surprise attack by Houthi rebels on the 10th, which caused the worst casualties in about a decade, killing 13 people and injuring over 300.

A subsequent attack on the 11th also left one person dead and more than 10 injured.

According to aviation data analytics firm Cirium, 99.7% of flights scheduled for King Khalid Airport on the 11th were canceled.

Flight tracking website Flightradar24 clearly showed passenger planes rerouting to avoid the airspace over Riyadh on the 12th.

However, airports such as Jeddah Airport, located on the west coast, are operating normally.

This marks the most severe flight disruption in the Saudi aviation industry in recent years.

It deals another blow to an aviation industry already struggling with the prolonged conflict in the Middle East and rising jet fuel prices.

Major global airlines have also successively grounded flights bound for Saudi Arabia.

Germany's Lufthansa Group completely canceled its flights to Riyadh until the 16th, and Air France-KLM extended its suspension of Riyadh routes until the end of this month.

The United Arab Emirates' Etihad Airways also canceled about 20 flights heading to Riyadh, Jeddah, and Dammam on the 12th and 13th.

Warnings from aviation authorities in various countries are also continuing.

The U.S. Federal Aviation Administration (FAA) urged its domestic airlines on the 11th to exercise extreme caution when flying to or over Saudi airspace.

The European Union Aviation Safety Agency (EASA) already expanded its alert for Saudi airspace on the 9th, citing the risk of missile and unmanned aerial vehicle (drone) attacks.