MOSCOW: Russian authorities have detained hundreds of migrant workers in a makeshift camp in Moscow as part of a widespread crackdown on illegal immigration.

Human rights campaigners have decried conditions in the camp, which is part of a planned national network of detainment centres to hold foreign nationals facing deportation.

More than 600 people were initially held in tents in the camp in an industrial area of Moscow, although there were reports that 200 were moved to formal detention centres on Tuesday. Opponents say the centres are illegal, comparing them to concentration camps or gulags.

“The paradox of a concentration camp for illegals is that the concentration camp itself is illegal,” writer and activist Oleg Kozyrev tweeted to more than 32,000 followers.

Russia currently has 21 detention centres for immigrants facing deportation, but authorities have prepared a bill that would create 83 special centres across the country’s 81 regions.

The immigrant crackdown began after a fight on July 27 at a Moscow market between natives of Russia’s Dagestan region and police who had come to arrest one of them on charges of rape. A relative of the wanted man struck an officer with brass knuckles, injuring his forehead. Much of the incident was captured on video in a clip widely circulated on the internet.

On July 29, police began raiding markets around the city and arresting immigrants whose documents were not in order, most of them from the Caucasus and Central Asia.

Of the 11 million immigrants in Russia, about three million have exceeded their visas and most are thought to be working illegally, according to the head of the migration service.

On July 31, law enforcement agents closed an illegal garment factory in an industrial area on the city outskirts, detaining at least 1,200 people, most of them from Vietnam. The next day police announced the creation of a temporary camp near the site of the illegal factory to hold some of the detained immigrants, who have 10 days to appeal against a deportation decision. Reporters who were allowed to visit the tents, pitched in a paved area that once held a market, described appalling conditions.

The interior ministry has claimed the site has a capacity of 900, but the Novaya Gazeta newspaper found immigrants crowded into cramped, stifling tents, with four outdoor showers and a long row of portable toilets.

The paper spoke to many held in the camp who had been unable to contact friends and relatives as there is no electricity to recharge their phones.

“It’s not the best conditions ... their telephone conversations are limited, and they’re under guard like in a prison,” said Bakhrom Khamroyev, an activist from the society Political Immigrants from Central Asia, who visited the camp.

But Khamroyev said the conditions were better than those in a municipal garage he visited outside Moscow, where 30 Uzbek workers arrested in a raid on Moscow’s Kommunarka market on Sunday. He said the immigrant workers, who were being guarded by men with machine guns, told him they had been beaten during the raid.

Ethnic tensions have flared up in Russia, with residents of the southern city of Pugachev taking to the streets protesting against arrivals from the Caucasus region after a Russian man was stabbed to death in a fight with a Chechen teenager.

“I don’t support this approach (of mass detentions) but it’s legal,” said Remat Karimov, a spokesman of the Labour Union of Migrant Workers.

“You need to wait until this is reflected in the fact that there will be no one to construct buildings, there will not be anywhere to eat in Moscow. If they employed these methods in Sochi it wouldn’t be possible to hold the Olympics because the buildings are being constructed by mostly illegal immigrants.”

By arrangement with the Guardian