"I assure you, and all those you serve, of the prayers and condolences of your brother bishops in England and Wales," he said, adding that "We, too, mourn this loss of life. We pray for the eternal repose of all who have died."
The Diocese of Salford announced that Bishop Arnold would say a special Mass for the victims May 23 at 12:30 p.m. at St. Mary's Church, which is the Catholic Mother Church of Greater Manchester. Another Mass will be held at the Salford cathedral at 7 p.m. local time.
In a May 23 statement immediately following a meeting of the government's emergency committee, Cobra, UK Prime Minister Theresa May called the bombing "a callous terrorist attack" that targeted "some of the youngest people in our society with cold calculation."
"Our thoughts and prayers are with the victims and the families and friends of all those affected," she said, noting that the attack is "among the worst terrorist incidents we have ever experienced in the United Kingdom."
"All acts of terrorism are cowardly attacks on innocent people," May continued, but said the arena attack stands out "for its appalling, sickening cowardice, deliberately targeting innocent, defenseless children and young people who should have been enjoying one of the most memorable nights of their lives."
Although he's traveling abroad, U.S. President Donald Trump said during a joint appearance with Palestinian Authority President Mahmoud Abbas Tuesday, that the "wicked ideology" of terrorism "must be obliterated."
"I extend my deepest condolences to those so terribly injured in this terrorist attack, and to the many killed and the families, so many families, of the victims."
"So many young, beautiful, innocent people living and enjoying their lives, murdered by evil losers in life," he added. "I won't call them monsters, because they would like that term, they would think that's a great name. I will call them, from now on, losers, because that's what they are."
The attack is the worst Britain has seen since a bombing on the London transport network on July 7, 2005 killed 52 people.
This article was updated at 2:00 p.m. local time in Rome with comments from a telegram sent by Pope Francis.