Jose Mourinho says the "hearts and minds" of everyone at Manchester United are with those affected by the horrific attack that killed 22 people and injured many more.
UEFA accepted United's request to cancel their press conference ahead of the Europa League final, while the team held a minute's silence at training before flying to Sweden.
"We are all very sad about the tragic events; we cannot take out of our minds and our hearts the victims and their families," the Portuguese said.
"We have a job to do and we will fly to Sweden to do that job. It is a pity we cannot fly with the happiness that we always have before a big game.
"I know, even during my short time here, that the people of Manchester will pull together as one."
Ajax Amsterdam boss Peter Bosz joined those expressing sympathy, shock and solidarity, with the atrocity taking the edge off the club's first major final in 21 years. "What happened in Manchester is something that we all feel at Ajax," he said. "The feeling that prevails is that the final doesn't have the glow it should have."