Bicycle terrorist attack threat has Amsterdam police on high alert

Update, 3:10 p.m., 29 December 2015: A response from Dutch authorities was added to this story.

The prospect of a terrorist attack around New Year's involving a bicycle or cargo bicycle containing explosives has the Amsterdam police on high alert. They will be extra vigilant in crowded places and around events during the turning of the year, Het Parool reports.

A message circulated through the Amsterdam Police states that there is still "no concrete evidence of a planned attack", but the "signals continue pointing to threat, especially between Christmas and New Year", according to the newspaper.

The police memo only states that a bicycle or cargo bicycle equipped with explosives may be used and asks officers to be extra vigilant around public venues and events up until New Year's, even in situations where no bikes are present. "Report suspicious behavior and conspicuous objects directly," it stated.

Amsterdam Mayor Eberhard van der Laan's office refused to comment. "We never make statements about any threat or eventual measures. We are of course alert around the holidays," the representative said.

The Amsterdam police's information service DRIO received the information from the intelligence services and can not provide any further details. A spokesman for the National Coordinator for Security and Counterterrorism said the details were part of a wider threat assessment report drawn up as a response to the Paris Attacks earlier this year, according to the Volkskrant.

Several European cities were cautioned of potential threats in the run-up to the New Year.