Thousands of people have been unable to make phone calls - including 999 calls - after a subsea cable was damaged by thieves trying to steal it.
British Telecom said it faces a major engineering challenge to restore service from the fibre-optic cable in Loch Carron. The thieves apparently believed it was copper.
The attempted theft disrupted services for more than 10,000 people.
Around 2,100 customers across nine communities in Skye, Lochalsh and the Western Isles lost their telephone, 999, and broadband services.
Engineers have since restored connections to eight of the areas, although 344 people still had no service by 11am.
Northern Constabulary say they have increased patrols in the area and set up 999 response points where members of the public can speak to a police officer.
Around 8,000 people in the north-west Highlands were also left without broadband, though this dropped to 7,000 by 10.30am.
BT said service to some mobile operators may also be disrupted.
A spokeswoman said: "The damage to the fibre cable was obviously caused at low tide at Strathcarron and when we were able to locate it, the tide had turned and the damaged area was 20 metres out into the loch. The next low tide is not until 2pm when we will make a concentrated effort to carry out a temporary repair with the help of local coastguards.
"We are continuing to investigate all our options including replacing the entire 1,000 metres of cable, and have alerted divers at our marine unit in Plymouth.
"This attempted theft is causing huge disruption of service and inconvenience to our customers but it is symptomatic of the times we live in. Metal theft is a growing problem affecting many industry sectors across the UK."
The nine areas first disrupted were Ardvasar, Balallan, Duntulm, Glendale, Glenshiel, Killilan, Scalpay, Skeabost and Uig. The damaged cable crosses Loch Carron between the villages of Lochcarron and Strathcarron.
Northern Constabulary said they had set up contact points at the Armadale Port offices, Barra police station and Glenshiel village hall.
Anyone needing police assistance can also contact Highland Council workers.
Metal theft is estimated to cost the UK economy as much as £770m a year. Earlier this week Justice Secretary Kenny MacAskill announced that hundreds of scrap dealers will have to be licensed as part of a crackdown the problem. He joined forces with the Association of Chief Police Officers in Scotland and British Transport Police to launch the Cut Out Metal Theft initiative.
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