A prominent critic of Ramzan Kadyrov's regime in Chechnya has gone missing, the newspaper Novaya Gazeta reported on Sept. 2.

Journalist Ruslan Martagov was last seen on Sept. 1 in Grozny, the republic’s capital. For years, human rights groups have denounced the Kadyrov regime for political oppression and rampant corruption.

Earlier this week, Human Rights Watch released a report detailing a new Chechen crackdown on critics — including “abductions and forced disappearances” — ahead of elections on Sept. 18, when Kadyrov will stand for re-election. Ramzan Kadyrov has ruled the Russian republic since 2007. His father, Akhmad Kadyrov, Chechnya's first president, was assassinated in 2004.

Martagov recently wrote about the public humiliation of some of Kadyrov's critics, as well as assaults on human rights activists and journalists, Novaya Gazeta reported.

On Wednesday morning, Aug. 31, Chechen Information Minister Djambulat Umarov reportedly telephoned Martagov and asked him to come in for questioning. He returned home in the afternoon, but was soon summoned again, that same day.

Said Selim Abdulmuslimov, a Chechen state official who reportedly attended the meeting, says Martagov and Umarov spoke privately, and Umarov then called Martagov a taxi. That was the last time anyone saw or heard from Martagov.

The journalist's friends and colleagues have expressed concerns that he could be the latest example of forced disappearances that have become a tactic commonly used against Kadyrov's critics in Chechnya. Martagov's family has informed the local authorities that he is missing, Novaya Gazeta reports.