The European Union’s top diplomat told Russian authorities on Friday that their treatment of jailed opposition politician Alexei Navalny represented a low point in ties as Navalny appeared in court again over a slander case.

Navalny, President Vladimir Putin’s most prominent critic, was jailed this week for almost three years for parole violations he called trumped up, a case that the West has condemned and which has spurred talk of sanctions.

Josep Borrell, the EU’s foreign policy chief, began talks with Russian Foreign Minister Sergei Lavrov on Friday. Ahead of those talks, he said he wanted to broach difficult issues like the Navalny case.

Lavrov said he was ready to engage and complained about the state of EU-Russia ties. He has previously accused the West of hysteria and double standards over the Navalny case, while the Kremlin has warned it will respond to harsh criticism from Borrell in kind.

Despite close trade ties and energy interdependence, Russia’s political relations with the European Union soured after Moscow annexed Crimea from Ukraine in 2014.

Navalny was back in court on Friday, accused of slandering a World War Two veteran who took part in a promotional video backing reforms last year that let Putin run for two more terms in the Kremlin after 2024 if he wants.

Navalny at the time described the people in the video as traitors and lackeys. He denies the slander charge.

“This case in general was intended as a kind of PR process because the Kremlin needs the headlines: Navalny slandered a veteran,” he told the court.

“I find it really disgusting and unbearable... You’ve been using him (the veteran) as a puppet... you’re making a mockery of a 95-year-old man.”

Though the charge is currently punishable by up to two years in jail, his lawyers say he cannot face a custodial sentence because the alleged crime was committed before the law was changed to make it a jailable offence.

Navalny’s jailing has sparked Western calls for his release and added a new irritant to strained relations between Russian and the West.