Over the weekend, officials in Brussels asked the public not to share its movements over social media to aid its raids against people allegedly tied to terrorist plots. Steven Vandeput, Belgium’s minister of defense, tweeted that the “police are asking the public not to report their movements on social media.” Vandeput asked for help and for Brussels citizens to retweet his message.

In response, people across Brussels and the world took to Twitter (TWTR) to share images of cats. Some Photoshopped pictures of cats in combat gear, while others took pictures of their cats with guns. The meme quickly went viral and it was hard not to find a #BrusselsLockdown tweet not accompanied by a sometimes-funny, sometimes-ironic cat image or video.

It’s perhaps nice to see that the people of Brussels were able to make light of a difficult situation. The Belgian government has said that Brussels is in immediate danger of a terrorist attack. Government officials have asked people across Brussels to stay away from subways, schools, and even windows. The lockdown is ongoing as law enforcement officials continue their string of raids.

Still, the social media display highlights the increasing importance services like Twitter and Facebook (FB) have taken on over the past several years. The very fact that law enforcement officials asked Twitter users not to share police movements is indicative of the service’s place as a destination for real-time news.

MORE: Brussels Remains on High Alert Amid Fears of Attack

Indeed, Twitter was home to the first reported mention of the raid on Osama bin Laden’s compound in Pakistan in 2011 after a user tweeted about it in real time. Similar scenarios have played out in much smaller and local raids both in the U.S. and abroad.

For law enforcement officials, such real-time reporting among citizens is a double-edged sword. In the case of Brussels, had certain raids and police movements been shared widely among users, those who had been targeted may have been tipped off and slipped out. Social media, however, can also be a useful tool. Alleged criminals may share critical information to their whereabouts on the services or, in some cases, the community may help law enforcement.

Such was the case in a recent incident in Florida when a woman was charged with driving under the influence. The woman took to her Periscope live-video-streaming service while driving. In the video, she said several times that she was “drunk” and after law enforcement was alerted, police were able to identify her location both by evaluating the videos and receiving tips from Periscope users. She was ultimately arrested.

In the fight with ISIS, social media has become the centerpiece of nearly all battles. Since the tragic attacks on Paris earlier this month, the hacking collective Anonymous, which has declared a cyberwar on ISIS, has used Twitter to share intelligence, updates on its operations, and more. The hacking collective has also targeted thousands of social media accounts allegedly tied to ISIS.

Meanwhile, #BrusselsLockdown continues. As of this writing, new images and videos of cats are hitting Twitter every few seconds. Now into its second day, #BrusselsLockdown appears to be a trend that isn’t going anywhere anytime soon.

Although Brussels police initially did not comment on the cat meme, officials on Monday decided to share in the #BrusselsLockdown fun, posting to Twitter an image of a bowl containing cat food.

“For cats who helped us last night,” the police tweet reads. “Help yourself.”

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