Shortly after Russian President Vladimir Putin arrived at EU headquarters for talks, four women -- stripped to the waist and with protest messages painted on their torsos -- began walking toward the building and shouting anti-Putin comments.
They were quickly arrested by police, and their demonstration caused no interruption in the conference, the website EUBusiness reported.
The Femen movement, established in Ukraine in 2008, is devoted to protests on women's issues, the Russian news agency RIA Novosti said.
The New York Times said discussions at the summit meeting were to include energy, trade and Syria.
Relations between the EU and Putin have been tainted by disagreements over gas pipelines, trade issues and human rights, the Times reported.
RIA Novosti said Putin would also push for legalizing visa-free travel, at least for business travelers. European officials have resisted the idea, fearing it will trigger a rise in crime and illegal immigration.