Alexei Navalny hospitalised after sustaining severe ‘swelling of the face’ while being held over demonstration calls.

Russian opposition leader Alexei Navalny, serving time in jail for calling for unauthorised protests, was taken to hospital after suffering an acute allergic reaction on Sunday.

Kira Yarmysh, Navalny’s spokeswoman, wrote on Twitter he was taken to hospital on Sunday morning with “severe swelling of the face and skin redness”.

She said the cause of Navalny’s allergic reaction was unknown and he had never suffered from such reactions in the past.

Navalny was jailed this week for 30 days for calling for an unauthorised march to protest against the exclusion of several opposition candidates from a local election later this year.

“It’s still unclear what’s wrong with him, but it looks strange,” Navalny’s lawyer, Olga Mikhailova, wrote on Facebook on Sunday evening.

She said Navalny had had “an acute allergic reaction to an unknown allergen and swelling of the face” and insisted he had had no allergies in his lifetime.

The Moscow hospital where Navalny’s spokeswoman said he was being treated could not be reached for comment.

Demonstration crackdown

Authorities say the opposition candidates were barred from local elections because they failed to collect enough genuine signatures backing them, an allegation they reject as false.

Police rounded up more than 1,000 people in the Russian capital at the rally on Saturday in one of the biggest crackdowns in recent years against the opposition, drawing international criticism.

The spokeswoman of the US embassy in Moscow, Andrea Kalan, wrote on Twitter on Sunday the large number of detentions in Moscow and the “use of disproportionate police force undermine rights of citizens to participate in the democratic process”.

The Polish Foreign Ministry in a statement called on Russian authorities “to stop using force against peaceful demonstrations and to refrain from arbitrary detentions”.

In a separate incident on Sunday, Russian activist Dmitry Gudkov, who was among the opposition candidates barred from running in local elections this year, said he had been arrested and taken to a Moscow police station.

The reason for Gudkov’s detention was not immediately clear, said his spokesman Alexei Obukhov.

Russia’s Interior Ministry did not respond to a request for comment on Navalny and Gudkov’s detention.

Obukhov said Gudkov, a former MP who challenged pro-Kremlin initiatives, had been arrested as he walked out of a shop near his home, where he had been buying food for the protesters still being held.

Navalny, Russia‘s most prominent opposition figure, has served several stints in jail in recent years for organising anti-government demonstrations.

The European Court of Human Rights last year ruled that Russia’s arrests and detention of Navalny in 2012 and 2014 were politically motivated and breached his human rights, a ruling Moscow called questionable.