Police were deployed into the stands at the Ryan McBride Brandywell Stadium after disorder broke out during a match between Derry City and CSKA Sofia on Thursday.

Before the Europa League clash between the home team and Bulgarian side got under way, disorder had broken out between rival supporters in Bishop Street in Londonderry which led to a police officer being injured and taken to hospital.

During the second half of the fixture, some fans – including parents with children – fled onto the pitch when further trouble occurred.

The MP for the area Colum Eastwood described the incident as “disgraceful” and said his party, the SDLP, “will demand answers” from the police about how it was handled.

The referee stopped the game for 14 minutes and police entered the stadium “at the request of Derry City Football Club and in the interests of public safety”.

PSNI Ch Insp Graeme Craig said police helped “restore calm, meaning that the match could continue to its conclusion”.

“Regrettably, this evening we have witnessed families and young children seeking refuge on the pitch because of the unacceptable and reckless behaviour of a small number of individuals, he added.

Police maintained a heavy police presence in the area for the remainder of the night.

Tiernan Lynch, Derry City manager, said he had “completely mixed emotions” about the game, which his team lost by a scoreline of two goals to one.

Though proud of his team’s performance, he said the occasion was tainted by “bottles being thrown” and scenes that Lynch feared could “get extremely nasty”.

Lynch’s son was in the stand, which caused him significant concern as he attempted to keep control on the touchline.

“My own wee man was in the crowd… I know how [others] felt; I didn’t know where he was,” he added.

Video footage of the trouble shows a section of the visiting support trying to get into the home section in the shared Southend Park stand.

There also appeared to have been drinks thrown.

SDLP councillor Rory Farrell was at the match with his 10-year-old daughter, Frida.

He said “things turned a lot more sinister”, when Derry City scored.

“They [CSKA fans] were hurling abuse, they were hurling objects, they were baying for blood, they were trying to force themselves through the barriers,” he told BBC Radio Foyle’s North West Today programme.

“I was looking at it, she was looking at it, everybody in that part of the stadium was just focused on what was happening.”

He said his only concern was for Frida’s safety.

Derry City fan Malcolm McCausland also witnessed the incident.

“Shortly after Derry scored, we witnessed an invasion of the Derry stand,” he told BBC Radio Foyle’s North West Today programme.

“I saw sights that I have never seen at a football match before.”

He said security at Brandywell – where there is normally not a police presence – would have to be reviewed in light of the trouble.

“A bunch of men and women in hi-vis jackets are not equipped to deal with this,” he said.

In a statement, Derry City Football Club said it “unequivocally condemns the violence witnessed at tonight’s match”.

“The club is working closely with UEFA, the PSNI, CSKA Sofia and our security partners to establish the full facts surrounding the incidents,” it added.

The MP for the area Colum Eastwood described the incident as “disgraceful” and said he would “demand answers” from the police about how it was handled.

The BBC has approached CSKA Sofia for comment.