* Human Rights Watch says workers rounded up in raids
* Says detainees targeted for non-Slavic appearance
* HRW says raids continued during IOC inspection visit
Russian authorities have detained hundreds of migrant workers in Sochi, the site of the 2014 Winter Olympics, and have held many of them in "arbitrary and inhuman conditions", Human Rights Watch said on Thursday.
Many of those detained in a wave of raids on work sites, homes and public places since early September helped build venues or infrastructure for the Games being held in the Black Sea resort city in February, the advocacy group said.
Most of those rounded up for alleged violations of migration or employment regulation were released after several hours but some have been held for more than a week, in some cases without access to a lawyer, Human Rights Watch said the group said.
No one at the Interior Ministry or the regional governor's office was immediately available to comment late on Thursday.
Citing a lawyer and a video he shot on a cell phone, Human Rights Watch said some 40 to 50 men had been held in a makeshift sheet-metal shed in a police station courtyard while police denied they were there.
Some of the detainees said they had been held there for days and some said they had not been given any food, a place to sleep or adequate shelter from the rain and cold, the New York-based rights group said.
The workers were detained during raids that began in early September and continued during the International Olympic Committee's final inspection visit before the Feb. 7-23 Games, HRW said.
"These abusive sweeps were happening right under the noses of the IOC during its inspection yet the IOC was totally silent about them," HRW quoted Jane Buchanan, its Europe and Central Asia associate director, as saying.
President Vladimir Putin, who has staked his reputation on the success of Russia's first post-Soviet Olympics, has said that Russia needs migrant workers in sectors like construction but that those who break the law should be punished.
The statement by Human Fights Watch adds to concerns aired by activists and Kremlin opponents over preparations for the Sochi Games, particularly a Putin decree restricting movement and public gatherings in Sochi that critics says is draconian.
Russia has come under fire from activists, and some athletes, for a law prohibiting gay "propaganda" among minors. Critics say it effectively bans gay rights rallies and could be used to prosecute anyone voicing support for homosexuals.
Putin has ordered law enforcement authorities to ensure security at the Olympics. Sochi is close to the North Caucasus, where Russia is fighting Islamist insurgents whose leader has said militants should prevent the Games taking place.
Many migrant workers from the Caucasus and Central Asia have worked on construction sites in Sochi, where most of the Olympic venues had to be built from scratch. HRW said many detainees were apparently targeted for their non-Slavic appearance.
IOC Sochi Coordination Committee head Jean-Claude Killy gave a positive assessment of preparations during the inspection visit last week, saying: "Everything is very impressive."