A 17,000-tonne drilling rig has run aground after being blown ashore on the Western Isles.
The Transocean Winner, which has diesel on board, was under tow west of Lewis when it was hit by severe storms.
It became detached from the tug boat overnight, before running aground at the beach of Dalmore in the Carloway area.
Stornoway Coastguard said there were no personnel on board the rig and there was no risk to life.
However, coastguard personnel have blocked access to the beach for health and safety reasons.
The Marine Accident Investigation Branch has begun an investigation into the incident.
The Maritime and Coastguard Agency (MCA) said it was monitoring for any pollution from the rig. The agency said Transocean Winner has 280 metric tonnes on board.
A spokesman said: "Following the grounding of the semi-submersible drilling rig Transocean Winner on the Isle of Lewis, the Secretary of State's Representative (SOSREP) for Maritime Salvage and Intervention Hugh Shaw is now in discussions with the owners Transocean and the salvors.
"The Maritime and Coastguard Agency's counter pollution branch and the SOSREP have both been monitoring the situation since yesterday evening and the local authority, police and Marine Scotland have all been kept informed."
Salvage company Smit has been mobilised to deal with the incident, the MCA added.
The Transocean Winner was being towed from Norway to Malta.
