About 1,000 Russian opposition supporters have held a rally in Moscow to support the more than 400 people who were arrested at a protest on the eve of President Vladimir Putin's inauguration in May.

The rally, held Thursday evening, was sanctioned by authorities, and police set up metal detectors at the entrance to demonstration site on a central Moscow square.

Police said one person was detained after he passed through the metal detectors and was found to be carrying a knife and several flares.

There was no immediate information on whether charges had been filed.