The Australian state of Victoria reported a more than 50% increase in new daily COVID-19 cases on Thursday. Health authorities have blamed the sudden surge in new cases on football parties held over the weekend, most of which had breached the state's social distancing rules.

The annual grand final was supposed to be held in Melbourne but due to the lockdown, Melbourne teams had to play the national premiership in the west coast city of Perth. During the event, Melbourne typically celebrates with a long weekend.

Health officials said that a third of the new cases reported, about 1,438 infections, were traced back to social gatherings that began on Friday, which was a public holiday. The state reported five COVID-19 deaths on Thursday and seven deaths on Wednesday.

The commander of Victoria's COVID-19 response, Jeroen Weimar, said the sudden surge could either be an isolated event or it could be a part of a new trend. Weimar said the surge highlights the consequences of people breaking the state's pandemic protocols and of letting their guards down.

"This is a direct consequence of hundreds of decisions made on Friday and Saturday last week and the question now is how we manage this going forward," Weimar said.

Officials had planned to lift Melbourne's lockdown on Oct. 26, when it believes that 70% of Victoria state's adult population should be fully vaccinated. As of Thursday, only about 49% of the state's adult population has been fully vaccinated. The delay had partly been caused by the delayed release of second doses to allocated more vaccines for first-time recipients.

The lockdown, which had been extended multiple times, has caused public protests. Residents have become increasingly frustrated as the city entered its sixth lockdown. By next week, Melbourne will hold the record as the city that has had the longest lockdown in the world.

Victoria has now overtaken its neighboring state of New South Wales, where the spread of the disease has largely been stabilized. New South Wales reported 941 new COVID-19 cases and six deaths on Thursday. About 63% of the state's adult population has been fully vaccinated.