The murder of a young football fan has led authorities in Greece to try and toughen the rules governing supporters' associations.
Alkis Kambanos was stabbed and severely beaten by a gang of youths in the northern city of Thessaloniki last week.
The 19-year-old victim supported the local side, Aris, while his attackers are allegedly fans of the rival club PAOK. Two others were also injured.
Nine people were arrested for the fatal attack on February 1. Arrest warrants have been issued for two more suspects.
The killing has drawn strong condemnation from political leaders across Greece.
"We will confront violent fans," government spokesman Giannis Oikonomou told reporters on Monday.
"It is our duty to society and especially to the younger generation, but also to our healthy sports community and the millions of good fans in our country."
Oikonomou said the government would submit a new bill to parliament next month, including harsher penalties and sentencing guidelines for violent football supporters.
The proposed legislation will also include a five-month ban on supporters' clubs, often used to stage attacks.
“Hooliganism is a global scourge that is responsible for the death of dozens of people," said Takis Theodorikakos, a Greek minister for public order.
"We must join forces, the government, political parties, football teams, and players. No one has the right to be absent from this effort to confront the violence.”
In the wake of the slaying, police raided multiple football fan clubs in Thessaloniki and the Greek capital Athens, confiscating several weapons.
The vice president of the European Commission, Margaritis Schinas — himself from Thessaloniki — visited the scene of the killing over the weekend with flowers.
"The violence, fanaticism and hatred of the few will not break us," Schinas wrote on Twitter. "Those of us who love and serve sports are the many and are stronger."
One of the suspects arrested by police has been charged with Kambanos' murder, while eight others appeared in court on Monday.
The rivalry between the two clubs' fanbases began in the interwar period, with Aris attracting the more affluent residents of Thessaloniki.
At the same time, PAOK garnered the support of ethnic Greek refugees, mainly from Asia Minor, who came to the region due to the 1923 population exchange with Turkey.