Egyptian authorities say they have arrested three divers trying to cut through an undersea internet cable.
The men were caught on a fishing boat just off the port city of Alexandria, said military spokesman Col Ahmed Mohammed Ali.
The damaged cable caused a drop in the speed of online services in Egypt and some other countries, said Egyptian news agency Mena.
It was unclear whether the incident was linked to cables damaged last Friday.
At the time, cable operator Seacom said several lines connecting Europe with Africa, the Middle East and Asia were hit, also slowing down internet services, reported Reuters news agency.
The cable hit in Wednesday's apparent sabotage was the South East Asia Middle East Western Europe 4 (SEA-ME-WE 4) - one of the main cables snaking under the Mediterranean, Mena said.
The attack took place some 750m (820 yards) north of Alexandria, it said.
In the statement on his official Facebook page, Col Ali said the divers were arrested while "cutting the undersea cable" of the main telecommunications company, Telecom Egypt.
He did not give any explanation for the divers' alleged motive.
The men were due to be interrogated.
Mediterranean telecoms cables have suffered disruptions several times in recent years, but they have usually been attributed to accidents involving ship propellers.