GORI, Georgia  Russian air attacks over northern Georgia intensified on Saturday morning, striking two apartment buildings in the city of Gori and clogging roads out of the area with fleeing refugees.

Russian authorities said their forces had retaken the South Ossetian capital, Tskhinvali, from Georgian control during the morning hours. They reported that 15 Russian peacekeepers and 1,500 civilians have been killed in the conflict.

Georgian forces shot down 10 Russian combat planes over the last two days, according to Alexander Lomaya, secretary of the Georgian National Security Council.

Shota Utiashvili, an official at the Georgian Interior Ministry, called the attack on Gori a “major escalation,” and said he expected attacks to increase over the course of Saturday. He said some 16 Russian planes were in the air over Georgian territory at any given time on Saturday, four times the number of sorties seen Friday.