Two Russian women have been convicted of plotting a terrorist attack on a shopping mall in the southern city of Rostov-on-Don and sentenced to long prison terms.

In a September 18 ruling, the North Caucasus Regional Military Court in Rostov sentenced Tatyana Karpenko to 14 1/2 years and Natalya Grishina to nine years, both in maximum-security prison.

In additional to plotting a terrorist attack, Karpenko was found guilty of recruiting a person for that purpose and illegally purchasing explosive substances, while Grishina was also found guilty of illegal possession of explosive substances.

Both women pleaded not guilty at their trial, which began in June.

Investigators claim that Karpenko and Grishina share the views of the extremist group Islamic State (IS) and the Caucasus Emirate, a militant Islamist organization carrying out an insurgency in the heavily Muslim North Caucasus region south of Rostov.

Prosecutors accused them of planning the attack from October 2015 to February 2016 and recruiting another woman, Viktoria Semyonova, as a suicide bomber. They said the plot was uncovered before the attack could take place.

Semyonova was tried separately and sentenced to three years in prison.

All three women have Slavic backgrounds, indicating that if they are Muslims they may have converted.

Based on reporting by Rapsinews, Interfax, and TASS