An oil rig that ran aground on Lewis has been connected to two tug boats ahead of an operation to free it on Monday night.

The Transocean Winner drilling rig was washed on to rocks at Dalmore two weeks ago after breaking its tow lines in high winds during transportation from Norway to Malta.

The 17,000-tonne semi-submersible rig has now been connected to two tugs as salvage teams prepare to refloat it at high tide at around 10.30pm.

The Maritime and Coastguard Agency (MCA) said: "Transocean plans to refloat the rig over the high water on Monday.

"The rig will then be towed to Broad Bay on Lewis and will remain there until it is in a stable and fit condition to be towed or transported to a suitable repair facility."

Hugh Shaw, the secretary of state's representative for maritime salvage and intervention said: "Good progress is being made in this operation.

"The plans for the refloat are in place although this is dependent on the salvage team being able to recover enough buoyancy to enable the rig to refloat safely."

The rig, which grounded on August 8 with 280 tonnes of diesel on board, lost up to 53,000 litres of fuel after two of its four fuel tanks ruptured.

The remaining 200 tonnes of hydrocarbons, mainly diesel with small amounts of base oil and brine, were transferred from the rig to the supply vessel Olympic Orion on Saturday.

The MCA said no pollution has been reported or observed, and plans to send an aircraft over the rig and surrounds to confirm the area is free of contaminants.

Members of the public planning to watch the refloat are being urged to be careful on the coastline.