Environmental campaigners have boarded an oil rig as it was being towed out to sea and are staging a protest onboard.
Greenpeace activists say they have scaled the 27,000-tonne rig - thought to be operated by BP - as it attempted to leave Cromarty Firth.
The protesters are calling for BP to end drilling for new oil wells and say they are prepared to stay on board the rig "for days".
At approximately 6.30pm on Sunday night, campaigners in a boat pulled up alongside the rig near Inverness, climbed aboard and unveiled a banner declaring a climate emergency.
Currently occupying a gantry on a leg of the rig below the main deck, the activists want to stop the drilling rig reaching the Vorlich oil field where it is believed to be trying to extract up to 30 million barrels of oil.
Jo, a Greenpeace activist from Scotland who is on board the rig, said: "Warm words flow from BP on their commitment to tackling climate change, yet this rig - and the 30 million barrels it seeks to drill - are a sure a sign that BP are committed to business as usual, fuelling a climate emergency that threatens millions of lives and the future of the living world.
"We can't let that happen - that's why we're here today.
"The Government may be bent on draining the North Sea of every last drop of oil, but this clearly contradicts their climate commitments.
"The perverse idea we must maximise our oil and gas reserves cannot continue.
"That means the Government must seriously reform the Oil & Gas Authority and instead invest heavily in the crucial work of helping oil communities like those in Scotland move from fossil fuels to the industries that will power our low carbon future."
Police Scotland said they were aware of an ongoing incident, but that the situation was currently within the jurisdiction of the Cromarty Firth's Port Authority.
A spokesman for the Port Authority said he was unable to comment at this stage, and BP has been contacted for comment.