Turkish President Recep Tayyip Erdogan is hosting NATO leaders in Ankara on Wednesday, while his main political rival defended himself against corruption charges in court.

Istanbul Mayor Ekrem Imamoglu, who represents the Republican People’s Party (CHP), was arrested in March 2025. Hundreds of party members and elected officials have been detained in what critics describe as a crackdown aimed at weakening Turkey’s largest opposition group.

In a specially built court near the Silivri prison complex outside Istanbul, Imamoglu protested the judge’s decision to bar him from attending hearings for nearly a week over “disruptive behavior,” saying his legal rights were being disregarded. “How can you explain to world leaders at the NATO summit, in Turkey, in Ankara, the silencing of Ekrem Imamoglu?” he asked the presiding judge, according to the opposition-backing Cumhuriyet newspaper.

Imamoglu was selected as the CHP’s future presidential candidate shortly after his arrest and is widely seen as the main challenger to Erdogan’s 23-year rule. The CHP’s leadership was removed by a court order that annulled its 2023 congress.

The government says Turkey’s judicial system is independent and free from political interference.

Wednesday’s hearing was for the largest case Imamoglu faces. Prosecutors allege he led a criminal organization as head of the Istanbul Metropolitan Municipality that was involved in widespread corruption. He faces 142 charges, including establishing what prosecutors called the “Imamoglu criminal organization for profit” tied to the period when he was mayor of Istanbul’s Beylikduzu district.

The indictment is described as 3,900 pages long and alleges the scheme’s goal was not only to provide financial benefit to Imamoglu and hundreds of co-defendants through bid rigging and payoffs, but also to fund Imamoglu’s rise within the CHP—ultimately culminating in his presidential candidacy.

Imamoglu told the court that prosecutors have not presented evidence supporting the case, saying that no evidence, documents, or audio recordings were offered to prove the allegations. If convicted, he could face a sentence totaling more than 2,000 years.

Prosecutors also announced a fresh investigation for “threatening a public official” after Imamoglu’s courtroom remarks, in which he said he would “judge those who prepared the indictment.”

The trial developments come as Turkey hosts attention on Ankara tied to the NATO summit.