Chelsea fans asked for evidence over safety concerns

Many Djurgarden fans bought tickets in home areas of Stamford Bridge

Chelsea fans have been asked to submit evidence to support concerns over their safety at Thursday's Conference League semi-final after Djurgarden fans had tickets for home sections of Stamford Bridge.

Videos shared widely on social media showed hundreds of supporters of the Swedish team stood in home areas of the stadium during the second leg which Chelsea won 1-0 to complete a 5-1 aggregate victory.

Some Djurgarden fans climbed over partitions to access the away section.

"This is the most serious breach of stadium security in recent memory, and it significantly undermines any security protocols Chelsea FC put in place," said the Chelsea Supporters' Trust in a statement.

The organisation added that it will "formally write a letter of complaint to Chelsea" calling for a "formal investigation into the tickets sale process" and the club's "security response during the match".

CST say its concerns about away fans accessing home areas were shared with senior club officials prior to the fixture.

Chelsea said the safety and security of supporters is "of paramount importance" and that increased restrictions were placed on ticket sales and distribution before the match.

"Despite these measures, we are aware of a large number of away supporters in home areas across the stadium," read a club statement published on Thursday night.

"We will be reviewing all ticketing arrangements and commit to implementing all necessary changes following this review. We will also share all our findings with the Fan Advisory Board."

A Metropolitan Police spokesperson said: "Officers were deployed to support stewards at Stamford Bridge last night after a number of away fans were identified in home stands. The fans had purchased tickets but not for the appropriate part of the ground.

"A number of away fans who had found themselves in the home stands climbed into the designated away stand where they remained without incident.

"Where away fans remained in home areas, officers and stewards provided a visible presence to ensure any incidents or altercations could be dealt with.

"While there were six arrests outside the ground for various offences including assault and possession of drugs, there were no arrests within the ground."

BBC Sport has contacted Uefa and Djurgarden for comment.

Chelsea's victory means they will play Spanish side Real Betis in the final, which is being held in Wroclaw, Poland on Wednesday, 28 May.