STORY: Video released by the German branch of the activist group Extinction Rebellion showed demonstrators sitting in entrances and glueing themselves to doors at the EC's Berlaymont building on Monday morning as workers were due to arrive.
Police detained a few of the demonstrators, with some being carried or dragged away from the entrances.
The group said on social media that 20 were arrested and that all had since been released. In a press release, Extinction Rebellion said 40 demonstrators took part, with 10 glueing themselves to doors.
Coming ahead of a European Council summit on June 23, the demonstration called for legislation to make ecocide - the deliberate or negligent destruction of the natural environment - punishable by law.