Social media accounts that support the Islamic State were very active leading up to the Manchester bombing that killed 19 and injured more than 50 others.

According to the Daily Caller, many of these accounts were calling on supporters to “hunt your prey” in the hours leading up to the attack.

The accounts provided information on U.K. community centers, government buildings and tourist areas, according to SITE Director Rita Katz. No group has claimed responsibility for the attack. However, ISIS accounts have celebrated the incident on social media. British counter-terrorism authorities are reportedly treating the event as a “possible terrorist incident.”

Users on a pro-ISIS forum referred to the attack as “a successful and surprising blow” against the U.K. and considered it revenge for the country’s participation in air strikes in Iraq and Syria, according to Katz.

While no one has claimed responsibility for the attack as of this time, many reports indicate that law enforcement is working with national intelligence agencies to uncover any and all information they can.