A rescue operation is under way after a diving support vessel with about 100 people on board ran aground on rocks at Lerwick harbour.

The 2,403-tonne Bibby Topaz was heading to the Gryphon oil field at about 0300 BST when it got into difficulty.

A Shetland Coastguard spokesman told BBC Scotland a tug was being sent to assist with the 106m-long vessel.

Rescuers are aiming to haul the vessel free at high tide, which is at about 1430 BST.

A spokesman for Bibby Offshore said: "None of the crew were injured in the incident and there has been no outflow of fuel or other pollution.

"The vessel, which had a pilot on board and the assistance of a manoeuvring tug at the time, is aground by the bow some 200m from the shore.

"Bibby Offshore are working with the authorities and expert parties to ensure that the vessel is refloated in a safe and timely manner."