MOSCOW, August 11 (RIA Novosti) - The Russian Federal Security Service (FSB) has detained 10 Georgian intelligence service officers who were preparing terrorist attacks, including in Russia, the head of the security service said on Monday.

"We have detained 10 agents of the Georgian special services who were spying on military facilities and preparing terrorist attacks, including on Russian territory," Alexander Bortnikov said at a meeting with Russian President Dmitry Medvedev.

Georgia launched major ground and air attacks to seize control of South Ossetia last Friday, prompting Russia to send in tanks and hundreds of troops. Around 2,000 civilians have since died in Tskhinvali, according to Russia. A total of 34,000 people are also reported to have fled across the Russian border.

As a result of the developing situation Bortnikov ordered the FSB, the Border Guard Service and the National Anti-Terrorism Committee to take measures to tighten border security in Russia's Southern Federal District.

"The situation in the Southern Federal District is complicated, but under control," Bortnikov told Medvedev.

He also said that the service had information that a group of 12 foreign mercenaries had entered Russia's North Caucasus Republic of Daghestan.

"We are currently working on this group with our partners from the Commonwealth of Independent States," he said.