The head of the prominent Russian human rights group Memorial's office in Chechnya has been detained on a drug charge, according to Chechen officials and a lawyer for the rights defender.

A fellow activist at Memorial dismissed the accusation against Oyub Titiyev as absurd, saying that it would be "more credible to accuse him of killing Napoleon."

Memorial had been struggling for hours to determine Titiyev's whereabouts and his fate after he failed to show up at a meeting with an acquaintance in the Kurchaloi district of the North Caucasus region early on January 9.

His disappearance underscored concerns about the risks faced by rights advocates, journalists, and opponents of Kremlin-backed Chechen leader Ramzan Kadyrov.

According to Memorial, the acquaintance said he saw Titiyev's car stopped by police on a highway after the two had planned to meet. Hours later he was told that Titiyev was at police headquarters in the town of Kurchaloi and saw Titiyev's car in the yard there.

But when Titiyev's lawyer arrived from the Chechen capital, Grozny, police in Kurchaloi told him that they did not have him in custody.

A leading figure at Memorial, Oleg Orlov, turned to President Vladimir Putin's advisory council on human rights and said through the council that he had received confirmation from Kheda Saratova, a member of Chechnya's human rights council, that Titiyev was being held by the Kurchaloi police.

'Climate Of Impunity'

Memorial voiced concern and demanded that the Russian government provide detailed information about Titiyev's whereabouts.

Later, Russian news agencies quoted Chechen officials as saying that Titiyev was detained on a charge of transporting drugs, and the independent newspaper Novaya Gazeta also quoted Titiyev's lawyer as saying that he was accused on a narcotics charge.

Government critics in Russia and other former Soviet republics say that the authorities sometimes use drug charges to justify illegal arrests.

Katya Sokiryanskaya, a board member at Memorial, said that Titiyev would be the third public activist to face a drug charge in Chechnya in recent years.

In a tweet, Sokiryankaya said that Titiyev was 60 years old, "never misses a prayer" and goes to the gym "every evening."

"It'd be more credible to accuse him of killing Napoleon," she wrote.

Activists say that Kadyrov, who was appointed to head Chechnya by Putin in 2007, rules through repressive measures and has created a climate of impunity for security forces in the province.

They claim that he bears responsibility for abuses, including kidnappings, disappearances, torture, and killings of political opponents.

"In recent years, Kadyrov has often publicly smeared and threatened rights activists, and some of those activists also suffered attacks and harassment by local security officials or pro-government thugs," Tanya Lokshina, Human Rights Watch’s Russia program director, said on January 9.

"There’s no doubt that Titiyev's arrest is an attempt to finally push Memorial -- which has been extensively reporting on collective punishment practices, enforced disappearances, torture, punitive house burnings, and other abuses by local authorities -- out of Chechnya."

Rights organizations have reported a steady increase in the number of Chechens detained or abducted by security personnel in the past two years, and say many of those who have gone missing have disappeared without a trace.

Natalya Estemirova, a Memorial activist who was investigating rights abuses in Chechnya, was kidnapped in Grozny and killed in 2009.

Kremlin critics say Putin supports Kadyrov, turning a blind eye to alleged abuses and violations of the Russian Constitution, because he relies on the former rebel to keep a lid on separatist sentiment and violence in Chechnya, the site of two devastating post-Soviet wars and an Islamist insurgency that spread to other mostly Muslim regions in the North Caucasus.