Internet and phone communications between Europe, the Middle East, and Asia have been seriously disrupted after submarine cables were severed.
It is thought the FLAG FEA, SMW4, and SMW3 lines, near the Alexandria cable station in Egypt, have all been cut.
A fault was also reported on the GO submarine cable 130km off Sicily.
Experts warned that it may be days before the fault is fixed and said the knock on effect could have serious repercussions on regional economies.
Jonathan Wright - director of wholesale products at Interoute which manages part of the optical fibre network - told the BBC that the effects of the break would be felt for many days.
"This will grind economies to a halt for a short space of time," he said "If you look at, say, local financial markets who trade with European and US markets, the speed at which they get live data will be compromised."
"If you think how quickly trades can be placed, if they are suffering from bad latency times, then by the time a trade is placed, the market may well have moved on."
The cause of the break is as yet unknown, although some seismic activity was reported near Malta shortly before the cut was detected.