Questions have been raised by concertgoers about the levels of security following the bomb attack at the Manchester venue that killed 22 people.

Shortly after the Ariana Grande concert ended at the Manchester Arena, a lone male suicide bomber detonated an explosive device at around 10.33 last night (22 May), sending debris and shrapnel in all directions.

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The venue, which can hold around 21,000 people, was starting to empty when the device was detonated in the foyer area.

People took to Twitter to criticise the levels of security at the area.

One person tweeted: "The last 3 times I've seen a show at Manchester Arena they didn't check my bag even though I had a backpack on."

Another tweeted: "For One Direction, they just kind of jiggled my bag, 'feeling' if there was anything harmful. Had a 1L bottle of Lucozade, didn't open my bag.

"Didn't even check my bag at all for Little Mix nor 5SOS, despite my bag being full and quite heavy."

Nikola Trochtova told Czech public radio "there was almost no security check, rather zero. They let us get in without any check if we have anything with us."

She added that "the only thing they were interested in was if we had any bottles of water with us. They almost didn't check our bags, they didn't take a look."

JB tweeted: "Being there at the concert in Manchester, I'm not surprised someone was able to take something into the arena. Security was horrendous."

Witnesses have described seeing glass, metal nuts and nails on the floor near to the scene of the attack, suggesting it may have been a form of nail bomb.

Often these are devices are pressure cookers filled with glass and nails sending shrapnel in all directions when detonated.

A vigil is set to take place in the evening in Manchester's Albert Square at 6pm today.

Manchester Arena and ShowSec, which is involved in security at the arena, have been approached for comment.