About 10 Greenpeace activists were detained but not arrested during a calm protest with Extinction Rebellion in Brussels on Wednesday morning over pollution and rising gas prices.
The action took place at about 07:00 on Place du Luxembourg in Ixelles, with no clashes reported.
At the same time, climbers were operating at the entrance to Place Solidarność, near the European Parliament.
At least four people were positioned around 10 metres above the ground.
Greenpeace regularly uses climbers to display messages on large buildings, bridges and other structures.
Organisers described it as a “spectacular action with climbers” staged on the eve of the European Council summit in Brussels on Thursday and Friday.
EU leaders are due to discuss European competitiveness and energy prices.
They will also examine temporary measures to ease the impact of high prices on citizens and businesses, as well as a longer-term strategy to reduce Europe’s dependence on fossil fuels.
