Tatyana Karpenko and Natalia Grishina denied plotting to kill shoppers in the city of Rostov in south-western Russia's Rostov Oblast region in 2015.
But a woman they had recruited to detonate a suicide vest while surrounded by shoppers confessed to her role in the plan.
As part of a plea bargain, Viktoria Semyonova received a lighter sentence of three years in a separate hearing.
Tatyana Karpenko (left) and Natalia Grishina (right) denied plotting to kill shoppers in the city of Rostov in south-western Russia's Rostov Oblast region in 2015
Karpenko (left) was jailed for 14 and a half years, while Grishina (right) received a lighter sentence of nine years
Karpenko, who has a three-year-old daughter, was found guilty of planning the attack and of recruiting Semyonova.
She will be jailed for 14 and a half years. She was also fined 150,000 Russian rubles, the equivalent of £1,900.
Grishina was also found guilty of planning the attack but not of inducing another person to commit a crime, and so received the lighter sentence of nine years. She was fined 100,000 Russian Rubles, or £1,270.
Read more: http://www.dailymail.co.uk/news/article-4899676/Two-women-Islamists-plotted-suicide-bomb-attack-Russia.html#ixzz4tIMgePl4
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