Around 80 protesters have gathered tonight at the perimeter of Shell's controversial Corrib gas pipeline site at Glengad beach near Belmullet Co Mayo.
Garda checkpoints and public order units have been in place for several hours and as many as 200 members of the force are on duty at the protest which is expected to continue into the early hours of tomorrow.
Notices were posted on a number of websites in Ireland and the UK calling for those who oppose Shell's project in Co Mayo to be in Glengad where the pipeline carrying gas from the Corrib fields is to come to shore.
The internet notices state the objective of tonight's event is to remove fencing erected around the landfall site on the beach.
Recent protests in the area have escalated into serious unrest after construction was recommenced at Glengad following a winter break.
On April 22nd, a gang of up to 15 masked men armed with chains and iron bars ran on to the Glengad site just before midnight.
Some of the group managed to start a mechanical digger and badly damaged the compound fence and gate, according to gardaí. Security guards ran for cover and effectively abandoned the site until back-up arrived in the early hours of the morning.
Rossport resident Willie Corduff lodged himself under a truck delivering security fencing to Glengad beach, and refused requests by gardaí and Shell security to leave.
It has been alleged that at about 3.40am, he came out from under the truck to stretch his legs and was removed from the site by force by masked men. Gardaí at the time confirmed Mr Corduff had been removed by security guards employed by Shell. A Garda statement said he had then been hospitalised as a precaution.
The Shell to Sea group has pointed out that Shell has been permitted to erect fencing around the construction site on Glengad beach despite having no planning permission to do so.
Last Friday, Minister for Community, Rural and Gaeltacht Affairs Éamon Ó Cuív and Minister for Energy Eamon Ryan urged all stakeholders in the conflict to "remain within the law".