More than 200 people are involved in the operation to refloat an oil rig which ran aground in the Western Isles.

The Transocean Winner rig was blown ashore in severe weather conditions on the western side of the Isle of Lewis last week when it detached from its tug en route from Norway to Malta.

The rig is believed to have leaked 50,000 litres of fuel, most of which is thought to have evaporated, but experts believe that there is no significant threat of pollution.

Salvage teams plan to transfer the remaining 137 metric tonnes of diesel fuel from the two intact tanks to tanks above the waterline.

Hugh Shaw, the secretary of state's representative for maritime, salvage and intervention, who is overseeing the operation, said: 'Work is ongoing and we are making steady progress, this is due to the response from all involved.

"We fully appreciate the support that we have been getting from the local community and its leaders, as well as all those who live and work on the island."

The Maritime and Coastguard Agency (MCA) said the salvage teams on board are continuing to examine possible refloatation and fuel transfer options.

A helicopter has made three trips to transfer additional salvage equipment to those on board the rig, which grounded at Dalmore beach near Carloway.

An MCA spokeswoman said: "So far, it is estimated that over 200 people are responding to the incident from the Maritime and Coastguard Agency, Transocean, Smit Salvage and Briggs Environmental.

"The 300m exclusion zone covering the sea and the exclusion zone covering the air (temporary) remains in place - any aircraft pilot or drone operator not involved in the operation that breaches that zone will be prosecuted."

Mr Shaw and Transocean staff are expected to give an update on the salvage plans at a public meeting in Carloway on Thursday evening.