MOSCOW — Russian Prime Minister Vladimir Putin said Thursday that government officials must crack down on migrant workers who break the nation’s laws by failing to register or get work permits, and on companies that profit by hiring them.

Putin, who is campaigning for Russia’s March presidential election, was addressing an issue that angers many Russians because Moscow is overrun with immigrants who often sleep in basements and overcrowded apartments.

Some 10 million labor migrants, mostly from ex-Soviet Central Asia, flock to Russia visa-free annually. Many face abuses, low pay and enslavement, while their presence triggers xenophobia and hate attacks in a country where unemployment stood at about 7 percent last year.

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