The younger brother of the Manchester Arena bomber is "just as guilty of the murder of 22 people" as his sibling, a court has heard.
On May 22 2017, Hashem Abedi's brother Salman detonated an explosive device as music fans left an Ariana Grande concert, killing 22 people and injuring many more.
Hashem Abedi, 22, is on trial at the Old Bailey accused of helping him plan the suicide attack.
Opening the case, prosecutor Duncan Penny QC said: "On the evening of Monday 22 May 2017 in the public foyer outside one of the entrances to the Manchester Arena in central Manchester shortly after the conclusion of a concert by the singer Ariana Grande, this defendant's brother detonated a large home-made improvised explosive device - a bomb packed with shrapnel contained in a rucksack on his back.
"The effects of the resulting explosion were both sudden and lethal.
"Twenty two people, men, women, teenagers and a child, were killed.
"Twenty eight people were very seriously injured, a further 63 people were seriously injured, 111 others were also hospitalised.
"In all, 237 were physically injured in addition to those killed, whilst a total of 670 people have since reported psychological trauma as a result of these events.
"The prosecution's case is that this defendant is just as guilty of the murder of the 22 people killed as was his brother.
"He is equally guilty of the attempted murder of many others and in doing so he was guilty of agreeing with his brother to cause an explosion or explosions of a nature likely to endanger life."
Mr Penny said Abedi had assisted and encouraged his brother.
Abedi allegedly obtained chemicals for a home-made bomb; got metal containers to construct it; found an address in Manchester to manufacture the explosive and store it and bought screws and nails for shrapnel.
In mid-April 2017, he also purchased a Nissan Micra to store bomb-making equipment, the court heard.
Mr Penny said the explosion was the result of months of planning, experimentation and preparation by the brothers.
He said: "The bomb which was detonated was self-evidently designed to kill and maim as many people as possible.
"It was packed with lethal shrapnel and it was detonated in the middle of a crowd in a very public area - the intention being to kill and to inflict maximum damage."
The court heard Manchester Arena was one of the largest in Europe with a capacity of some 21,000 people.
The foyer, known as the City Room, was a meeting point for parents and family to collect young concert-goers.
At the end of the concert, the area was very busy and amid the throng, carrying a heavy rucksack containing a homemade bomb, was Salman Abedi, the defendant's brother, the court heard.
The device was packed with shrapnel made of nuts, cross dowels and screws, jurors were told.
At 10.31pm, Salman Abedi detonated the bomb, leaving 19 people dead at the scene and a further three mortally wounded.
Mr Penny said: "Such was the ferocity of this explosion that Salman Abedi was dismembered in the process.
"The scene that met the survivors and those that attended thereafter was one of destruction and chaos."
Abedi, originally from Manchester, denies 22 counts of murder, attempted murder and conspiring with his brother to cause explosions.
The 22 were: off-duty police officer Elaine McIver, 43, Saffie Roussos, eight, Sorrell Leczkowski, 14, Eilidh MacLeod, 14, Nell Jones, 14, Olivia Campbell-Hardy, 15, Megan Hurley, 15, Georgina Callander, 18, Chloe Rutherford,17, Liam Curry, 19, Courtney Boyle, 19, Philip Tron, 32, John Atkinson, 26, Martyn Hett, 29, Kelly Brewster, 32, Angelika Klis, 39, Marcin Klis, 42, Michelle Kiss, 45, Alison Howe, 45, Lisa Lees, 43, Wendy Fawell, 50 and Jane Tweddle, 51.