Two police officers were injured Monday in scuffles that broke out when protesters tried to break through a police cordon during a demonstration against a meeting of oil and gas companies in Vienna.
Police detained 143 people and resorted to using pepper spray to break up the demonstration.
Austrian public broadcaster ORF reported that some protesters had tried to block roads leading to the hotel where the three-day European Gas Conference is being held.
Environmental activists have criticized conference participants for pursuing further natural gas projects amid strong demand and high prices due to the war in Ukraine.
Jasmin Duregger of the group Greenpeace accused gas companies of promoting their business at the expense of the climate "under the cover of energy security."
Activists hope to mobilize for a large protest Tuesday against the conference, which is sponsored by Austrian energy giant OMV.
