Several people were detained and beaten in the Belarusian capital Minsk on Tuesday as they attempted to hold a rally calling for a nationwide boycott of this weekend's parliamentary elections in the former Soviet republic.
"Opposition activists were going to hold another picket near the Frunzensky store in Minsk calling on people not to vote in the elections to the Chamber of Representatives of the National Assembly," the opposition Charter 97 group said on its website.
Photojournalists for Associated Press and Reuters were among those held, reports said.
Footage uploaded to the social networking site Facebook suggests they were manhandled by security officers as they were being led away.
A camera crew from German TV channel ZDF is also reported to have been detained.
Belarusian President Alexander Lukashenko has faced mounting international criticism in recent years for the heavy-handed tactics of his security forces in suppressing street protests against his almost two-decade rule.