UPDATE:

DANDRIDGE, Tenn. (WVLT) - TWRA just confirmed with Local 8 News that a second body has been recovered from Douglas Lake.

The names of the two men identified are James Brannan of Illinois, and John Perez of Indiana.

TWRA reported the two were riding behind a pontoon boat on a tube. However, Brannan fell out when the boat turned around, and Perez jumped in after him. The people on the boat told investigators that they never saw them return to the surface.

After searching for almost two days, both of their bodies were found at the bottom of the lake.

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DANDRIDGE, Tenn (WVLT) -- What was a rescue mission has turned into a recovery operation. TWRA believe the two men drowned after Thursday's incident. They are still searching for the men at this time. Their names aren't being released.

The search was called at 9:30 Thursday night after it got too dark. Rescuers will meet in the morning to start looking again.

The Tennessee Wildlife Resources Agency says the two men, ages 53 and 39, were riding behind a pontoon boat on a tube. TWRA says the 53 year-old man fell out when the boat turned around, and that the 39 year-old man jumped in after him.

The four people on the boat never saw either man emerge from the water, and called 911 at 6:27 p.m.

James McAfee, a public information officer for TWRA in this accident, says the men were not wearing life jackets. At the speed the boat was traveling, he says a flotation device would have likely kept them afloat.

"The boat would've turned and picked them up. You're supposed to wear a life jacket," said McAfee.

The accident happened in the McGuire Creek area of Douglas Park, but the launch point of the rescue was in Dandridge. McAfee says it took 30 minutes to reach the site by water.

Rescuers searched for more than two hours, but left the water at 9:30, still no sign of either swimmer.

"At this point, they have not been recovered. No one has seen them, and we're hoping they may swim to shore. Hopefully," said McAfee.

McAfee says crews will meet for an all-call at 8:30 at the Jefferson County Rescue Squad. He says they should be back in the water to search for them at 9:00, hoping daylight will bring good news.