According to the UK Independent, Islamic State (ISIS/ISIL) supporters celebrated the Brussels bombings online, even before the Islamic State formally took responsibility for the attacks:

“What a beautiful day today,” one man wrote, calling the victims “Belgium supporters” who did not count as civilians. “F*** Belgium. Belgium wanted to bomb the Islamic state Now enjoy what your hands have sown. “A lot of duas [prayers] were answered today.” The supporter claimed to have received a message from an Isis militant to the group’s supporters in Belgium reading: “We have come to you with slaughter.”

Heavy.com has more tweets from the ISIS militant who said, “We have come to you with slaughter,” including, “When Muslims are bombed they run towards the bombing. When kuffar are bombed, they run to another city” and “Metro is controlled by NATO. Western security is so pathetic. Without their planes they are nothing.”

Arabic supporters of ISIS got a #BrusselsOnFire hashtag rolling on Twitter, as they used #ParisOnFire to celebrate after the Paris massacre.

“The state will force you to reevaluate your ways a thousand times before you are emboldened to kill Muslims again, and know that Muslims now have a state to defend them,” said one Islamic State devotee on the hashtag, spotted by the New York Post.

NBC News reports that a widely retweeted post among ISIS backers declares, “What will be coming is worse.”

#BrusselsIsOnFire tweets reported by The Jerusalem Post include, “You declared war against us and bombed us, and we attack you inside your homeland,” an ISIS supporter declaring he was shedding “tears of joy” over the massacre, and the ever-popular “Allahu akbar.”

The JPost notes that in addition to celebrating the attacks as revenge for Western airstrikes against the Islamic State and the arrest of Paris attack conspirator Salah Abdelsalam in Brussels, ISIS fans were excited about the degree of economic damage that would be inflicted on Belgium and the European Union by Tuesday’s lockdown of transit systems and airports. This would help fulfill the Islamic State’s desire to “devastate the Western economy and replace the dollar with its own coin as the only international legal tender.”

According to International Business Times, Twitter administrators “quickly” shut down the #BrusselsIsOnFire hashtag and deleted many of its posts, in addition to suspending some accounts that violated Twitter’s terms of service by “directly or indirectly promoting violence.” In addition to belligerent threats and celebrations of murder, some violators were pushing out disinformation, such as false warnings of a bombing at the European Commission offices.

IBT reports that ISIS channels on the secure chat system Telegram were urging supporters to flood Twitter with propaganda messages on several Brussels-related hashtags, anticipating a crackdown on terrorist-supporting accounts.

According to Business Insider, among the messages ISIS wanted its supporters to post on Twitter, in the French language, were, “We will kill you all with knives, guns, and bombs” and “Expect more bombs, more death! Coming soon in Germany!”