Jailed Istanbul mayor faces trial amid crackdown on Turkey's opposition

Istanbul's jailed mayor Ekrem Imamoglu goes on trial on Monday in a sweeping corruption case that could extinguish the ambition of Tayyip Erdogan's main rival to become president at Turkey's next election.

Imamoglu, 55, is the chief suspect among more than 400 defendants linked to the Istanbul municipality accused of corruption and bribery. He and his main opposition Republican People's Party (CHP) deny the charges, which carry prison sentences adding up to hundreds of years.

The case is being held at a courthouse in the Silivri prison complex west of Istanbul, where Imamoglu has been held for almost a year, and is the centrepiece of a judicial crackdown on the CHP that is overshadowing politics ahead of elections that are expected to be held next year.

In comments to Reuters, Imamoglu struck a defiant tone, saying Erdogan should call elections right away, but his prospects of challenging the veteran leader look bleak amid a crackdown that rights groups and foreign observers say has undermined the democratic credentials of NATO member Turkey.

"(I)t's hard to avoid the conclusion that prosecutors are trying to remove Imamoglu from politics and discredit his party in ways that undermine democracy," said Benjamin Ward, the deputy Europe and Central Asia director at Human Rights Watch, describing the trial as coming after more than a year of "weaponising" the criminal justice system against the CHP.

The government denies exerting influence over the judiciary, which it says is independent.

Newly appointed Justice Minister Akin Gurlek, who as chief Istanbul prosecutor led investigations into Imamoglu, said he carried out his duties in the case without bias or consideration for the mayor's position.

"I simply did my duty as a public prosecutor. My conscience is clear," Gurlek told reporters in comments published on Friday.

Imamoglu has already suffered a severe blow to his presidential ambitions, with a court in January rejecting his lawsuit challenging the cancellation of his university degree – a qualification required of any presidential candidate.

Erdogan, 72, has led Turkey as prime minister or president since 2003. Presidential and parliamentary elections are not scheduled until 2028 but if he wishes to seek a third term as president he is obliged to hold the vote early, unless the constitutional term limits are changed.