A British government minister has called for a "full disclosure" of all evidence on the Hillsborough Disaster in which 96 Liverpool fans died.
The victims were crushed to death during Liverpool's FA Cup tie with Nottingham Forest on 15 April 1989.
Andy Burnham, Secretary for Culture, Media and Sport made his comments on Wednesday after being heckled by angry fans at an emotional memorial service at Anfield on the 20th anniversary of the tragedy.
The families are still fighting for a full inquiry into the disaster.
On the day of the tragedy, Liverpool supporters were in the Leppings Lane of the Sheffield stadium.
South Yorkshire Police, which oversaw the event, opened a large exit gate which forced too many Liverpool fans on to the terrace, leaving the fans inside trapped between people entering the ground and the metal fences at the front of the stand.
The disaster and subsequent inquiry led to the removal of fencing at the front of stands and all-seater stadiums, changing the culture of grounds and creating a safer if less boisterous atmosphere at matches.
On Wednesday, the 25,000-strong crowd at Anfield sang Liverpool's anthem You'll Never Walk Alone and a candle was lit for each victim during the memorial service.
Two-minute silences were held in Liverpool, Sheffield and Nottingham at 3.06pm, the time the match was abandoned. At Anfield the crowd chanted: "Justice for the 96" during the minister's speech.
Mr Burnham urged the police and medics, as well as the local council, to publish all material relating to the disaster to help families discover what happened to their loved ones.
"If there is further information held by public bodies relevant to the tragedy that has not yet been published then it should be," he said.
"I believe now the public interest lies very clearly in full disclosure of all such information, so that the families and others can make their judgement on all the facts."
Families still seeking full inquiry
The families are angry that no one has been successfully prosecuted despite an official report in 1989 criticising police for their failure to control the situation.
Families have been fighting for a fresh inquest to be held, unhappy at the decision by the coroner at the original 1991 inquest to limit the scope of his review.
The coroner said the victims were all dead or fatally injured by 3.15 pm but the families argue that cut-off meant they never discovered what happened to their relatives and prevented an official probe into the emergency services' response.
They also accuse police of a cover-up and of trying to place the blame on supporters' behaviour.
The Hillsborough Families Support Group vowed the fight for justice would continue.