RNA - "Firefighters put out a blaze in an old house lacking windows for ventilation," the civil defense stated in a message posted on Twitter on Wednesday.
"Eleven people died of asphyxiation" in the southern province of Najran, it added.
The blaze also left six workers injured.
According to the report, the victims were Indian and Bangladeshi nationals.
Millions of poor Asians are working in the Persian Gulf states. Human rights groups say many of the workers suffer exploitation and abuses, including non-payment of wages.
According to latest official figures released in 2015, there are nine million foreigners currently working in Saudi Arabia, many of them South Asians.
Rights groups have urged the Persian Gulf kingdom and other Arab states to end the "kafala" sponsorship system, which forces foreign workers to seek their employer's consent to change jobs or leave the country, a measure rights groups say leaves workers open to exploitation.
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