Workers at Shell were prevented from leaving the building after members of Extinction Rebellion superglued themselves to the entrance of their office, just before lunchtime too.
"Met Police say three men have been arrested so far on suspicion of criminal damage".
Extinction Rebellion plan to carry out disruption protests during tomorrow and Wednesday's morning rush hours.
At Waterloo Bridge, protesters blocked the crossing over the Thames and turned it into an impromptu garden bridge, with people bringing trees, flowers and setting up a miniature skate park and stage.
Financial Times also noted that Extinction Rebellion makes a point of having demonstrators arrested; in the last six months or so, over 200 people affiliated with the movement have been arrested.
Among a total of 113 arrests, five people were detained on suspicion of criminal damage at Shell's headquarters.
Protesters will gather at Marble Arch, Oxford Circus, Waterloo Bridge, Piccadilly Circus and Parliament square, peacefully blocking traffic and creating a "festival" of action including people's assemblies, speeches, performances, workshops and food.
Anna Burton, from Lancashire in northwest England, said she came to the protest to call on big businesses to go carbon neutral and demand a better ecological future for her children.
Organisers said: "The worldwide rebellion begins and Extinction Rebellion will be bringing London to a standstill for up to two weeks". One Shell spokesman told CNN: "We respect the right of everyone to express their point of view, we ask only that they do so with their safety and the safety of others in mind".
Extinction Rebellion have organised a nationwide week of action, they are calling for a full-scale Rebellion to demand decisive action from governments on climate change and ecological collapse. In the letter, they warn they would escalate their disruptive actions over the coming days and weeks unless the government acts.
Savannah, a protester for Extinction Rebellion, defended the protests and said the group want to start important conversations.