Hillsborough campaigners have taken to the streets of Liverpool to gather a petition calling for criminal charges to be brought over the disaster.
About 25,000 people attended a memorial service last month to remember the 96 Liverpool fans who died during the club's FA Cup semi-final 20 years ago.
Since then pressure has grown on the government to make public bodies release all files about the tragedy.
The petition will be delivered during a march to Downing Street on 20 June.
Supporters from campaign group, March 4 Justice have pledged to gather 100,000 signatures for the petition before is presented to the government during the march.
Barry Thompson from the group said: "If we can get as many people as possible, and as many signatures as possible, in front of No 10 Downing Street then we think that the government will listen, and that they will re-investigate what happened at Hillsborough."
On the day of the tragedy, on 15 April 1989, the victims were crushed to death during Liverpool's FA Cup tie with Nottingham Forest in the Leppings Lane end 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.
Families of the victims have led a two-decade long campaign for a full inquiry into the disaster.
At the recent memorial service at Anfield, culture secretary Andy Burnham, was heckled by angry fans calling for 'Justice for the 96', which prompted him to call for all files to be made public.
Trevor Hicks, chairman of the Hillsborough Families Support Group (HFSG), said: "The decision was to stand fully behind the M4J campaign."
March 4 Justice was set up in the days after the 20th anniversary to bring together fans who wanted to get involved in a mass march for justice.