A rule of thumb, in cases like this, is to ask who benefits from this. The cable connects Europe and Asia, and so would affect all or most Eurasian countries to a greater or lesser extent. Further, as traffic is redirected through intact cables, there could be indirect effects across the world. Finally, the perpetrator must be capable of cutting not one but four metre-thick cables at the bottom of the sea.
Once you consider these points, there is only one possible suspect.
Where are you getting metre thick from? I'm seeing that modern cables tend to be around 1 inch. Maybe these are special cables, but I don't see that. These things get cut by anchors sometimes. I could imagine what it would be like to get snagged on 4 metre thick wires. Some of them aren't even that deep. Some divers tried cutting wires near egypt 10 years ago.
If they didn't do it intentionally. One of the theories is that the ship they sank dragged its anchor across the cables. It can't really be confirmed until the evidence has been collected, but it sounds plausible.
Why? Probably because they recently published a map of all the cables and then made a comment to the effect of "Hey, look at all this important infrastructure that goes right through our area!"