Old Trafford’s flags flew at half-mast on Tuesday morning in the wake of the horrific terror attack in Manchester on Monday night.
At least 22 people including children have died and 59 further injured after a male suicide bomber targeted an Ariana Grande concert at the Manchester Arena.
Both Manchester United and Manchester City have paid tribute to the victims and their families, while Old Trafford paid its respects by flying their flags at half-mast.
United have also asked Uefa for permission to don black armbands for the Europa League final against Ajax in Stockholm on Wednesday night.
The Premier League side recently wore armbands for the victims of fans who died in Calabar, Nigeria after an electric cable fell on supporters in a bar.
Anti-terror cops have now thrown an impenetrable ring of steel around United’s clash at the Friends Arena in Sweden amid heightened fears of an attack.
Jose Mourinho‘s stars are being protected around the clock by gun cops as they prepare to take on Ajax.
But the mood among travelling fans was sombre in the wake of an attack which injured dozens and cast a shadow over the city.
A heavy police presence has dominated Stockholm since Monday, with police helicopters circling the skies and armoured cars patrolling the streets.
Uefa themselves have released a statement ahead of the game on the back of Monday night’s horrendous event.
The statement read: “There is currently no specific intelligence which might suggest that any of the Uefa Europa League final activities in Stockholm may be target of attacks.
“Uefa has been closely working with local authorities and the Swedish FA for many months and the terrorist risk has been taken into account since the very beginning of the project.
“Furthermore, a number of addition securing measures were implemented following the attacks in Stockholm last April.
“Due to tight security arrangements, Uefa urges fans to arrive at the stadium as early as possible, as detailed checks will be made at the entrances, resulting in potential delays in accessing the stadium.”
Meanwhile, a Man United spokesman said: “We are reviewing our security plans and have been working through the night.
"Meetings will take place today to decide how to proceed.”