By Alissa de Carbonnel and Thomas Grove
MOSCOW, Oct 15 (Reuters) - Russian police detained a migrant worker suspected of killing an ethnic Russia and stepped up security in Moscow on Tuesday to try prevent a repeat of the race riots that were unleashed by the man's death.
Advocacy groups warned migrants from ex-Soviet states of Central Asia and the Caucasus of a high risk of violence as crowds of Muslims celebrated the Islamic holiday of Eid al-Adha, and a heavy police presence was seen in the capital.
Police said they had detained a native of the mostly Muslim state of Azerbaijan, Orhan Zeynalov, who is suspected of fatally stabbing 25-year-old Yegor Shcherbakov in front of his girlfriend while they were walking home on Thursday night.
The murder triggered Russia's worst race riots in three years near Moscow's southern Biryulyovo district, where Shcherbakov was attacked.
Tensions simmer in Moscow between disenchanted ethnic Russian youths and labour migrants mostly from predominantly Muslim ex-Soviet states.
Police said Zeynalov resisted special forces when they tried to detain him in Kolomna, a small town outside of Moscow, Russian news agencies reported.
Outside Moscow's main mosque, police set up barriers and metal detectors to control the flow of people. Ethnic tension is often higher during the Islamic holiday because crowds spill out into the streets around the city's few mosques.
Crowds of residents in Biryulyovo have called for tougher policing of migrants and roamed the streets hunting for men who matched a police description of Shcherbakov's alleged killer.
One of Russia's main Muslim organisations said its website was also hacked on Tuesday.
On Sunday, rioters smashed shop windows, clashed with police and stormed a market in Biryulyovo where many migrants work.
The violence was the worst in Moscow since 2010 when some 7,000 nationalists rallied near the Kremlin, chanting racist slogans and attacking non-Slavic-looking passers-by in what then-President Dmitry Medvedev called "pogroms".
On Monday, police also raided the market in Biryulyovo and detained more than 1,200 people to check for any wrongdoing, and about 450 migrants were detained at another site.
In an apparent move to appease residents, Moscow's police chief fired the senior officer in the district on Tuesday.
Migrant labour has played a significant role in Russia during an oil-fuelled economic boom that took off around the time President Vladimir Putin came to power in 2000.
But many in the capital resent the migrants, and some Russians have called on the government to impose visa requirements for people arriving from Moscow's former satellites. (Additional reporting by Maria Tsvetkova and Ian Bateson,; Editing by Steve Gutterman and Alison Williams)