ROSTOV-ON-DON, October 8 (RIA Novosti) - A total of 624 residents of six towns in the Stavropol Territory, southern Russia, have fallen ill in a case of mass food poisoning that has hit nurseries, local emergencies officials said on Monday.

As many as 572 children under 14 have been struck by a stomach virus since Wednesday as a result of the outbreak.

Earlier reports said at least 396 were hospitalized with acute intestinal infection, 356 of them children.

A preliminary probe carried out by Russia's consumer rights watchdog, Rospotrebnadzor, revealed that the infection may have been spread by a Vita fermented milk drink supplied to the nurseries.

This is the fourth outbreak of the infection in the Stavropol Territory to date. Over 500 people fell ill in the region with food poisoning between July and September.