Images of cats have flooded Twitter under the hashtag #Barcelona. This comes following response to a police request not to show images of the dead and badly injured during an ongoing terrorist attack.
The response is a genuine, if quirky, effort to respect the police's wishes as they continue to hunt the driver of a truck that sped down Las Ramblas in the heart of the Catalonian city on 17 August.
Cat pictures were also uploaded to Twitter en masse as a 2015 terrorist attack in Belgium unfolded. after police asked internet users not to disclose their movements.
Local media have reported that 13 people were killed this afternoon as a truck drove down the popular tourist destination at high speed. Scores of others have been wounded.
A manhunt is now on to find the driver and a possible accomplice with some reports that a Turkish restaurant has been held up with hostages inside.
Spanish police have identified Driss Oukabir as the man suspected of carrying out a terrorist attack that killed at least 13 people in Barcelona's Las Ramblas, according to newspaper El Pais.
Scores of people have been injured in the "massive crash", according to police, with local media reporting that the driver fled the vehicle on foot after the crash.
Oukabir is believed to be of Moroccan-French descent and living in the Spanish town of Ripoll.
Police are urging people to stay away from the area around Plaça de Catalunya, the city's central square where the main train station is located.