Qatar Telecom (Qtel) said on Sunday the cable was damaged between the Qatari island of Haloul and the UAE island of Das on Friday.
The cause of damage is not yet known, but ArabianBusiness.com has been told unofficially the problem is related to the power system and not the result of a ship’s anchor cutting the cable, as is thought to be the case in the other three incidents.
It is expected to take at least "a few days" to fix, according to one person with knowledge of the situation.
The damage caused major problems for internet users in Qatar over the weekend, but Qtel’s loss of capacity has been kept below 40% thanks to what the telecom said was a large number of alternative routes for transmission.
It is not yet clear how badly telecom and internet services have been affected in the UAE. Etisalat is expected to release a statement on Monday.
Parts of the Gulf Arab region were plunged into a virtual internet blackout on Wednesday when two undersea cables were cut near Alexandria, on Egypt’s north coast.
The initial breaches were in segments of two intercontinental cables known as Sea-ME-We-4 and Flag Europe-Asia.
The situation was made worse on Friday when Flag, part of India’s Reliance Communications, revealed a third cable, Falcon, had also been damaged off the UAE coast.
Etisalat said it does not use the Falcon cable and is therefore unaffected, but the UAE’s second telco, Du, warned the damage could hamper its efforts to restore normal service to customers. Etisalat said it is helping Du minimise disruption.
Flag said a repair ship was expected to arrive at the location of the third damaged cable in the next few days, but bad weather has prevented the vessel from setting off from Abu Dhabi port.
The ship is now expected to depart Monday morning and the repairs should take five days.
The third cable is located 56 kilometres from Dubai on a segment between the UAE and Oman.
Etisalat said it had been informed by Flag Telecom, which operates one of the two damaged cables in the Mediterranean Sea, that the problem should be fixed in two weeks, while the operator of the other cable planned to carry out repairs on February 8.
Flag said on Saturday a ship should reach the cable repair ground by February 5.