Lawyers for Indonesia’s opposition called on Friday for President Joko Widodo’s election victory to be annulled, telling the country’s Constitutional Court it had been achieved through “systematic electoral fraud and abuse of power”.

Official results released by the General Election Commission last month showed Widodo, or Jokowi as he is commonly known, beat Prabowo Subianto, a retired general, by 11 percentage points in the April poll, winning more than 55 percent of the votes. His rival has refused to concede defeat.

“We are filing a lawsuit against the General Election Commission (KPU), demanding that the KPU annul its decision on the result of the presidential election,” Bambang Widjojanto, the chief lawyer representing Prabowo, told the court on Friday.

The dispute has led to weeks of uncertainty in the world’s third-largest democracy and violence broke out last month after the results were announced when Prabowo urged his supporters to protest in the capital.

Eight people were killed and more than 900 hurt in the clashes. Police have arrested dozens of alleged instigators, including a close ally of Prabowo who is suspected of orchestrating assassination plots against top government officials.

Earlier this week, Prabowo, who had previously warned of “people power”-style street protests, told his supporters to remain calm while the Constitutional Court deliberates the merit of the claim.

Tight security

Around 17,000 police and military personnel have been deployed to prevent a repeat of the unrest. A small group of opposition supporters held a peaceful protest near the heavily protected court building, with some holding placards saying: “We demand justice!”

Prabowo and his campaign team want the court to annul the official result, disqualify Jokowi and his running mate as candidates, or hold another election. The court is expected to deliver a verdict by June 28.

The legal team pointed to issues with Jokowi’s campaign financing and use of state apparatus as a campaign tool, saying the official election result came about because of “illegal actions, fraud and abuse of power which are structured, systematic and massive”.

The election supervisory agency has said previously there was no evidence of systematic cheating and independent observers have said the poll was free and fair.

Legal representatives for the KPU and Jowkowi’s campaign team were present at the hearing and were expected to make statements later on Friday.