ISIS has praised Salman Abedi, the suspected Islamic extremist who carried out a deadly terrorist attack at an Ariana Grande in Manchester, England, and warned of future "more severe attacks on the worshipers of the Cross and their allies."

At least 22 people were murdered --including children -- and 59 others were injured in the suspected terror attack Monday night, which police believe was carried out by an "improvised explosive device."

Online, ISIS supporters began celebrating the attack, and the group officially claimed responsibility on Tuesday through its Amaq News Agency, according to the SITE Intelligence Group.

"With Allah's grace and support, a soldier of Khilafah managed to place explosive devices in the midst of the gatherings of the Crusaders in the British city of Manchester, in revenge for Allah's religion, in an endeavor to terrorize the mushirkin and in response to their transgressions against the lands of the Muslims," the statement said. "The explosive devices were detonated in the shameless concert arena, resulting in 30 Crusaders being killed and 70 others being wounded. And what comes next will be more severe on the worshipers of the Cross and their allies, by Allah's permission. And all praises is due to Allah, Lord of the creation."

The statement called him a soldier of the caliphate says the attack was meant to terrorize the "mushirkin," which means pagans or those who worship a false idol, according to Heavy.com.

CBS News reported that the Abedi was a suicide bomber who traveled to the concert on the subway to Victoria Station and later detonated the explosive device outside of the packed arena as people were leaving the concert. The outlet says the bomb wielded by Abedi was "designed to kill and maim as many people as possible; many of the survivors suffered shrapnel wounds and ball bearings were found at the scene."

While experts are somewhat skeptical of ISIS' claim of responsibility, saying the details of the statement do not match up with the actual events, police nevertheless said they are investigating the attack as a "terrorist incident until we have further information."

British Prime Minister Theresa May said in a statement early Tuesday morning that officials "are working to establish the full details of what is being treated by police as an appalling terrorist attack. All our thoughts are with the victims and the families of those who have been affected."

She also said the attacker had deliberately chosen "his time and place to cause maximum carnage" in the young crowd.

U.S. President Donald Trump also weighed in on the attack, saying, "So many young, beautiful, innocent people living and enjoying their lives murdered by evil losers in life. I won't call them monsters because they would like that term, they would think that's a great name. I will call them losers because that's what they are. They're losers. And we'll have more of them. But they're losers, just remember that."

Meanwhile, a number of Christian leaders took to social media to express their outrage over the event; Franklin Graham, president of Samaritan's Purse, urged believers to "continue to pray for the injured victims and the families who have lost loved ones dear to them" and that "God would give wisdom to our leaders in combatting this and the courage to identify what it is by name--Islamic terrorism."