Another Yemeni Houthi missile or drone attack, or a local accident?

A massive fire broke out Sunday at the the Haramain high-speed rail station in Saudi Arabia’s coastal city of Jeddah, and upon early reports the cause is as yet unknown.

Social media videos showed giant plumes of black smoke rising high above the train station and city in what's clearly a very significant incident.

Breaking: Massive fire engulfs train station #Jeddah which links Makkah & Madina. Chaos is starting to spread in #Saudi Arabia pic.twitter.com/mxvv8p05MD #SpencePorter

— Ali AlAhmed (@AliAlAhmed_en) September 29, 2019

As Reuters reports:

Plumes of black smoke were still rising from the roof of the station at least four hours after the fire broke out at 12.35 p.m. (0935 GMT), Al-Ekhbariya state television footage showed.

It said civil defense were fighting the fire with air support and many sections of the blaze were under control.

At least five have been reported transported to a local hospital with injuries, with hundreds of emergency responders at the scene of the blaze.

A fire in Haremeyn Train Station in #Jeddah #SaudiArabia

pic.twitter.com/vRaDXb1bhe

— nonouzi (@Gerrrty) September 29, 2019

Emergency fire suppression helicopters could be seen hovering over the train station's expansive roof in a situation which doesn't yet appear to be under control.

The high-speed rail has been described as "a centerpiece of a new multi-billion dollar high-speed rail project" related to the kingdom's Vision 2030 project.

The terminal is a crucial link for Muslim pilgrims traveling to the country's holiest Islamic sites, per Reuters:

The 450-km (280-mile) Haramain Railway linking the two holiest cities in Islam, Mecca and Medina, with the Red Sea city of Jeddah, was opened in 2018 and cost 6.7 billion euros ($7.3 billion).

The high speed rail is also seen as central to crown prince Mohammed bin Salman's efforts at drastically modernizing Saudi infrastructure to boost tourism, in order to eventually wean the economy off oil revenue dependency, in preparation for a post-oil future.

The emergency incident comes following the Sept. 14 drone and missile attack on Saudi Aramco facilities, and amid soaring regional tensions with Iran, and as war rages on across the kingdom's southern border in Yemen.

Civil aviation works on rescuing detainees at the Haramain high speed train station in #Jeddah.
•
No injuries reported until this moment. pic.twitter.com/mk5WJXq2YG

— مهند أبوعبيد Mohannad AbuObaid (@mohannadObaid) September 29, 2019

developing...