MOSCOW, August 12 (RIA Novosti) – Police said they have detained hundreds of illegal immigrants in weekend raids in at least eight of Russia’s 83 regions, following similar operations in the country’s two largest cities, Moscow and St. Petersburg.

The biggest sweep was Tyumen Region in western Siberia, where 800 were held on suspicion of working in Russia illegally, local police said Monday.

Some 570 Chinese working in greenhouses in the southern Krasnodar Region without work permits were held, fined a combined 924,000 rubles ($28,000) and deported, regional police said. Another 100 were caught in the neighboring Volgograd Region, local law enforcement officials said.

Police in the Perm Region reported checking 413 foreigners working at local marketplaces, but did not say how many were found to be violating migration rules.

Another 200 “illegal migrants” were held in Moscow Region on Friday, local police said, though the raid was not reported until Monday.

Checks also took place in Kamchatka Region and the Republic of Udmurtia, but resulted only in a few arrests. In Novgorod Region, not a single illegal immigrant was found in marketplaces in the region’s eponymous capital, police said.

About 1,000 people have been held in Moscow since late July on suspicion of working in the country illegally, the majority being Vietnamese citizens.

Some were released and 31 were deported Saturday, but more than 500 remain housed in an improvised tent camp in eastern Moscow. Rights activists have criticized the camp for what they claim are poor conditions, and have questioned its legal status and the validity of the charges against some of the inmates.

The Moscow authorities plan to relocate the detainees to more comfortable children’s camps around Moscow, but have given no timeframe, the Kremlin’s rights council said Friday.

Moscow mayoral candidate Sergei Mitrokhin from the opposition Yabloko party toured the capital’s immigrant detention camp this weekend and reported no violations.

“Bath station is working fine, the toilets are clean. Not the best food, maybe, but nutritious. Could use a bit more canned meat in their rice, perhaps,” he was cited as saying.

In St. Petersburg, local nationalists armed with baseball bats staged a series of vigilante anti-immigrant raids earlier this month, making “document checks” at the city’s fruit markets.

The raids, which their organizers called “pogroms,” were initially condoned by the police at their own admission, but ended with the arrest of two dozen participants and two criminal cases on hooliganism charges.

The recent crackdown on immigrants follows a fracas at a Moscow market in late July, when a policeman was seriously injured in an attack by a worker while trying to detain a sex offender.

The attacker was, in fact, a Russian citizen from the North Caucasus – a predominantly Muslim region whose residents are often treated as migrants outside their home turf – who said he mistook the officers for racketeers. The incident nonetheless boosted anti-immigrant sentiment across the country.

Russia hosts up to 10 million “illegal migrants,” the head of Russia’s Federation of Migrants, Muhammad Amin Majumder, told Rusnovosti.ru Sunday. Governmental agencies have quoted a figure of about 3 million foreigners illegally living in Russia, which has a population of 141 million.

The immigration issue remains a problematic one for the Russian government. Public opinion remains solidly anti-immigration. In a poll in July by Russia’s Levada center, a third of respondents cited an “influx of other ethnicities” as the biggest threat to national security.

The government, however, is also aware that Russia’s shrinking labor force is putting pressure on business, with sectors like construction highly reliant on migrant workers.