MOSCOW: The European Union's top diplomat was on Friday expected to challenge Moscow over the detention of Alexei Navalny and a fierce police crackdown, as the prominent Putin critic was due again in court on defamation charges.

Josep Borrell's visit to Russia is the first by a senior EU envoy since 2017 and follows terse exchanges between Moscow and the bloc whose ties have been deeply strained since the Kremlin annexed Crimea in 2014.

European countries sharply condemned Russia's response to a recent wave of nationwide anti-Kremlin demonstrations, which saw 10,000 people detained and spurred allegations of police abuse.

They also demanded that Moscow release Navalny who was handed a jail term this week and spent months recovering in Germany from a poisoning attack.

Ahead of Borrell's meeting with Foreign Minister Sergei Lavrov on Friday, the Spanish diplomat said Russia and the EU see each other as "rivals and competitors".

"We have strong disagreements when it comes to the conflicts in our immediate neighbourhood, from Ukraine and Belarus to Libya and Syria, and when it comes to human rights and fundamental freedoms," he told the Interfax news agency.

"We have made our position very clear on the poisoning of Alexei Navalny, his arrest and that of thousands of demonstrators over the past days," Borrell added.

President Vladimir Putin's spokesman said before Friday's meeting that Russia wants an improvement in relations with the EU and to reopen dialogue.

But Dmitri Peskov conceded that unresolved differences between Russia and the EU were "pretty big" in number.

Navalny, 44, survived the attack with Novichok in August and returned to Russia last month even though authorities said they would seek his arrest.

After being imprisoned on Tuesday for two years and eight months on old fraud charges, Navalny was due in court again Friday for allegedly defaming a World War II veteran.