(QHA) - Russian authorities say they have detained five members of a "banned international terrorist organisation" in the restive North Caucasus region, according to BBC. The arrests were made in the town of Nalchik, some 300km (185 miles) east of the Black Sea resort of Sochi, the host of next month's Winter Olympics. Russia earlier announced it was deploying more than 30,000 police and interior ministry troops to the region. The main concern is the threat of attack by Islamist militants. Security fears have been heightened after two suicide bomb attacks killed 34 people in the southern city of Volgograd on 29 and 30 December. No group has said it carried out the attacks, but Russia's most wanted man, Chechen rebel leader Doku Umarov, has previously urged his fighters to target the Games.