MOSCOW (Reuters) - Russian police have started detaining people gathering in central Moscow for an opposition protest on Saturday that had been declared illegal by the authorities, Reuters reporters on the scene said.

OVD-Info, the monitoring group, said 26 people had been detained.

Reuters witnesses said the detained people were being sent to police buses parked along Moscow’s Tverskaya Street ahead of the protest planned for 1100 GMT.

Police earlier detained prominent members of the opposition ahead of the protest against what the opposition says is the unfair exclusion of a raft of opposition-minded candidates from a Sept. 8 local election in Moscow.