Brussels entered the third day of a city-wide lockdown today, as Belgian police continue to search for suspected terrorists accused of planning an "imminent" attack. Authorities announced that 16 suspects had been detained in a counterterrorism raid last night, though Salah Abdeslam, who is believed to have been involved in last week's Paris attacks, was not one of them.

Prior to last night's raid, Belgian police asked that internet users not tweet anything about the operation, for fear that the information would tip off their targets. Apparently, it worked. Instead of posting details about the raid, Belgians flooded the #BrusselsLockdown hashtag with photos of their cats.

It's not entirely clear how the trend started, but the AFP reports that it may have been launched by Dutch cameraman Hugo Janssen, who tweeted: "Instead of tweets about police activity in Brussels, here’s a picture of our cat Mozart." Within hours, the hashtag was flooded with cats, memes, and even a few dogs posted by Twitter users around the world.

Belgian officials thanked the internet for its compliance once the raid was over, though Brussels remains on high alert. Universities, schools, and the city's metro have all been closed.