A Russian opposition group has said its activists threw tomatoes at Dutch King Willem-Alexander and his wife, Queen Maxima, as they arrived for a concert in the capital, Moscow.
Eduard Limonov, the leader of the banned National Bolshevik party, said two of its activists hurled tomatoes at the royals on Saturday.
Russia's state security agency said they missed their target.
Limonov said the action was intended to attract public attention to what he called the Netherlands' failure to properly investigate the death of the group's member, Alexander Dolmatov, who committed suicide in January at a Dutch deportation centre.
The royal visit was aimed to celebrate the two nations' historical ties, but it came amid tensions caused by Russia's seizure of a Dutch-flagged Greenpeace ship and other disputes.