MOSCOW (Reuters) - Ramzan Kadyrov, the hardline pro-Moscow head of Russia's Northern Caucasus Republic of Chechnya, said on Sunday that more than 50 suspected militants were detained in the biggest sting operation of recent years.

Moscow has waged two wars against separatists in the predominantly Muslim region since the collapse of the Soviet Union in 1991. The region is now ruled by Kadyrov, a former rebel fighter now loyal to President Vladimir Putin.

Civil rights activists accuse Kadyrov of arbitrary arrests of dissidents.

Kadyrov said on his Instagram account that a group directed by a Chechen-born militant based in Syria had been targeted.

"As of now, all the band-group was neutralized, more than 50 of its participants were delivered to police stations," Kadyrov said. http://bit.ly/2jd2Z7i

The security situation in the North Caucasus region remains volatile as unemployment and corruption is rife, pushing some young men to embrace radical versions of Islam.

Some Chechens are known to be fighting as committed jihadis on the side of Islamic State in Syria and Moscow fears they may return to attack Russia, something they have threatened to do.

The Kremlin has justified its campaign of air strikes in Syria by saying its main objective was to crush Islamic State.

(Reporting by Vladimir Soldatkin; Editing by Catherine Evans)