Critic of Chechen president Ramzan Kadyrov abducted in Moscow

Fears for safety of Russian human rights campaigner Arbi Khachukayev after he is flown to Chechnya

Luke Harding in Moscow

A Russian human rights group today said that gunmen loyal to Chechnya's pro-Kremlin president had abducted a human rights activist in Moscow and flown him to Chechnya.

Chechen security officials grabbed Arbi Khachukayev this afternoon and then bundled him on to a flight to Chechnya's capital, Grozny, Memorial said. Its staff were deeply concerned for his safety, it added.

Khachukayev runs a Chechen human rights organization, Law. It has exposed human rights abuses allegedly committed by forces loyal to Chechnya's Kremlin-appointed president, Ramzan Kadyrov. Last night Chechnya's interior ministry claimed that Khachukayev had been seized for taking part in an "armed assault".

"He's now back in Chechnya," a human rights worker, Svetlana Gannushinka, told the Guardian. "It's not clear whether he's a hostage or a defendant. As soon as I found out about his kidnapping I faxed the office of the interior ministry at Vnukovo airport. They didn't answer."

She added that Khachukayev had been allowed to phone his relatives.

The activist was based in Grozny but had recently fled Chechnya amid concerns for his security in the wake of the killings of other rights workers, she suggested.

A string of political rivals and human rights activists critical of Kadyrov have been murdered in recent years – including Anna Politkovskaya, the journalist, writer and campaigner who was murdered outside her Moscow flat in October 2006. Kadyrov has denied involvement in her killing, remarking: "I don't kill women."

In July, gunmen abducted Natasha Estimerova – the head of Memorial's Chechnya office – from outside her flat in Grozny. They drove her to the neighboring republic of Ingushetia and then killed her by the side of the road. Kadyrov had previously summoned Estimerova to a meeting and expressed his intense displeasure at her work.

Earlier this year a Chechen exile, Umar Israilov, who had made detailed allegations that Kadyrov had tortured him in a secret jail near Grozny was gunned down while leaving a supermarket in Vienna. Israilov had complained about Kadyrov to the European court of human rights. Another critic, Sulim Yamadayev, was killed in his Dubai garage.

Rights groups claim that Kadyrov's forces are responsible for abductions, torture, punitive house burnings and extra-judicial killings of people suspected of ties to Islamists.

Kadyrov's critics say that by backing him Moscow has encouraged a climate of impunity that encourages unchecked brutality. The Kremlin has shrugged off the criticism. It praises Kadyrov for pacifying the southern Russian region, despite overwhelming evidence that the insurgency there continues.