More than 130 people were arrested after defying police instructions not to cycle near the Olympics venues in east London during the opening ceremony, Scotland Yard said.
They were held for breach of Section 12 of the Public Order Act and for causing a public nuisance, a spokesman said.
Officers were aware that a monthly cycle procession was due to take place, and made several attempts to engage with riders to discuss their plans, he added.
"The procession usually attracts approximately 100 cyclists, but on this occasion around 400-500 people gathered near Waterloo at approximately 6pm. Officers believe this may have included other individuals or groups not normally part of the monthly procession.
"As the procession last night had the potential to cause serious disruption to the life of the community, the Metropolitan Police Service applied conditions under Section 12 of the Public Order Act. The participants in the procession were informed of these conditions."
The conditions included that it should end no later than 3am today, that participants must not enter any part of the Olympic Route Network (ORN), and participants must remain south of the River Thames.
The cyclists moved off from about 6.30pm and from the outset they attempted to cross the Thames, despite attempts by officers to prevent them, the spokesman said.
"The procession split into smaller groups and some of them crossed to the north of the river.
"They travelled to the Stratford area, where there were large numbers of people and vehicles due to the Olympic Opening Ceremony.
"Cyclists continued to ride around the ORN, despite numerous warnings, and officers took action to detain the cyclists and over 130 people were arrested for breach of Section 12 of the Public Order Act.
"Our position on protest is clear - people have a right to protest, it is an incredibly important part of our democracy. We want anyone who wants to protest to come and speak to us so we can work together to ensure that their point can be made.
"What people do not have the right to do is to hold a protest that stops other people from exercising their own rights to go about their business - that means athletes who have trained for years for their chance in a lifetime to compete, millions of ticket holders from seeing the world's greatest sporting event, and everyone else in London who wants to get around."
A spokesman for the group Occupy London said that at about 9pm a kettle was imposed on more than 100 cyclists at the junction of Stratford High Street and Warton Road, where they were held for most of the opening ceremony.
"We estimate that over 100 have been arrested and taken to police stations around London," he said.