Climate change protesters have set up camp close to the Royal Bank of Scotland headquarters in Edinburgh.
The Camp for Climate Action is angry about the banking group's role in financing oil industry developments which they believe could be dangerous for the environment.
Dozens of protesters are in an open area close to the building, which is to the west of Edinburgh.
RBS said its offer to meet with the protest leaders had been declined.
Police made two arrests at the site on Wednesday night. Officers are currently surrounding the building, along with security staff.
The environmentalists have criticised the banking group for backing the fossil fuel industry in the UK and around the world.
There has been particular anger about moves to exploit Canadian tar sands for commercial oil production.
The protesters say they do not rule out taking direct action against the RBS headquarters building itself.
The protesters claim about 100 activists "swooped" on the grounds of RBS at Gogarburn at about 2115 BST on Wednesday. They said this happened a day earlier than planned so they could "outfox" the authorities who were keen to prevent the camp from taking place.
The location of the site was announced through a mass text message that campers were subscribing to.
They have set up marquees, eco-toilets and kitchens and the organisers said hundreds of activists would be arriving at the camp over the next few days.
A spokesman for RBS said: "In recent years RBS has been one of the most active banks in the world in providing funding for renewable energy projects so we are at the forefront of helping finance the transition.
"Therefore, while we understand the protesters' intent and publicity tactics we clearly cannot agree with their decision to target RBS.
"We have offered to meet with the leaders of the protest, and although they have not accepted, this offer still stands.
"Our top priority is securing the safety of our staff and customers and we urge the protesters to make their point peacefully."
One of the protesters, Ruth McTernan, said: "It's been a dramatic start to what's going to be a week full of workshops, sustainable living and direct action against RBS crimes against the climate.
"We're in a beautiful location here at Gogarburn, surrounded by the woods.
"People should come down, have a cup of tea and check out what's going on for themselves."
Activists have declared a day of mass action against the Royal Bank of Scotland on Monday.
The protesters said Thursday's swoop would still take place but only at the bank's St Andrew's Square base.