Russian authorities say 10 people from Central Asia with links to the Islamic State have been arrested after planning attacks in Moscow and St. Petersburg. The Federal Security Service said in a statement Saturday that the 10 individuals had all been detained with the help of Tajikistan and Kyrgyzstan. They were planning attacks using homemade explosives and assault rifles in public places. Thousands of Russian citizens are thought to have joined the Islamic State in Syria, and authorities have repeatedly warned that many former Soviet republics are fertile ground for young Islamic State recruits. The terrorist group has ramped up its threats against Russia after the Kremlin intensified air strikes in Syria in recent months.