Law enforcers in the Russian capital have discovered "a whole town" of makeshift cabins in Moscow, where about 2,000 illegal migrant labourers live, RIA Novosti reported.
The discovery was made after residents complained about their noisy neighbours.
A probe showed that the land, which was leased by authorities for agriculture purposes to a farm, "was de facto turned into a major supplier on the Moscow labour market", a law enforcement official said.
Buses arrived there in the morning, took labourer migrants to construction sites all over the city, and took them back in the evening, the source said.
This is not the first time such settlements have been found in Moscow.
In April 2011, Moscow police discovered what it called an "underground city" of labourer migrants in an abandoned bomb shelter.
A total of 110 men and women were living in an underground bomb shelter behind a four-metre high concrete barbed wire fence. The facility had showers, bedrooms and even prayer rooms.
Russia has been struggling to stem the inflow of migrant workers, most of whom come to Moscow and other major cities from former Soviet republics. Around 10 percent of Russia's workforce is thought to come from outside the country.