TASHKENT (Reuters) - Uzbekistan has abruptly recalled thousands of school teachers, college students and healthcare workers from cotton fields, halting a practice condemned abroad as forced labor, government officials and other sources told Reuters on Friday.

The Central Asian nation is one of the world’s leading cotton exporters and for years it has mobilized the students as well as staff at schools and clinics to pick the autumn harvest.

It phased out using minors in 2015 under international pressure that included boycott campaigns.

Officially, the work is voluntary and paid at about $0.005 per kilogram. In reality those who refuse risk expulsion or the sack unless they bribe an official or hire someone to work in their place, sources said.

The harvest started this month but late on Thursday the Tashkent government ordered the cotton pickers home, said a district official who spoke on the condition of anonymity because he was not authorized to comment.

The government declined to comment.

A central government official who also asked not to be named said an order barring the use of such workers had in fact been issued in August. On Thursday Tashkent warned regional governors they would be sacked if they fail to comply with it.

The district official said regional governments have been ordered to hire unemployed locals for cotton picking instead.

Several students and a school director, who all requested anonymity, said they had been ordered to return to class or had their trips to the field canceled at the last moment.

Despite ending the use of child labor, Uzbekistan ranked among the top five worst offenders in the Global Slavery Index compiled last year by activist group Walk Free Foundation.