MOSCOW — Ivan Pavlov, the lawyer for jailed Kremlin critic Aleksei Navalny’s Anti-Corruption Foundation (FBK), has been detained for allegedly disclosing classified information relating to an ongoing investigation.

The Team 29 lawyers’ group that Pavlov leads said on Telegram early on April 29 that Federal Security Service (FSB) officers detained Pavlov after searching his hotel room in Moscow, adding that the St. Petersburg home of the group’s IT specialist, Igor Dorfman, was also searched.

The TASS news agency cited a source in law enforcement structures confirming that Pavlov was detained.

According to Pavlov’s colleagues, he is accused of disclosing classified information relating to an ongoing investigation, an offense punishable by up to three months in jail.

Pavlov and his team specialize in high treason, espionage, and cases related to state security. He is a lawyer of former journalist Ivan Safronov, who was charged with treason and was scheduled to attend a court hearing in Moscow on April 30 that would decide on an extension of his pretrial detention.

On April 29, Pavlov represented Navalny’s FBK at a Moscow court hearing over a prosecutor’s request to label the group an extremist organization.

Pavlov also defended physicist Viktor Kudryavtsev, who was charged with high treason. Kudryavtsev died of cancer on April 29 at the age of 78 as his trial was pending.

A day before his detainment, Pavlov accused the FSB of causing Kudryavtsev’s death, saying that the 14 months spent by Kudryavtsev in pretrial detention “completely damaged his health.” He added that Kudryavtsev’s case is “an example of how secret services are literally killing Russian science in general.”