Iran has long been monitoring and even mapping US military bases in Arab countries — but has been less involved in Saudi Arabia.
Experts say this may be due to a potential embargo or heightened tensions between Saudi Arabia and Iran over the presence of US bases.
However, yesterday evening there were reports of US warplanes flying from Europe to the Middle East, and some were reportedly stationed in Saudi Arabia and other nearby areas.
This morning, for the first time since the start of this tension, Iran sent a direct message to US military bases in Saudi Arabia.