The following script is from "The Warlord" which aired on April 14, 2013. Lara Logan is the correspondent. Peter Klein and Jeff Newton, producers.
Very little is known about a sensitive mission being carried out by a hundred U.S. Special Operations troops deep in the jungles of central Africa. They've joined several thousand African soldiers in one of the biggest manhunts that's ever taken place. Their goal is to help kill or capture the world's most wanted warlord, Joseph Kony and destroy his army.
This mission is part of a broader U.S. effort to counter the emerging threat to America from the growth of terrorist networks across Africa.
Joseph Kony has been on a murderous rampage that has lasted almost three decades, killing thousands and building one of the biggest armies of child soldiers in history.
Kony started out in northern Uganda, but his campaign has spread to four countries and he's now operating in this vast, lawless area in the center of Africa.
Our story, which includes images you may find disturbing, begins in the Central African Republic, with an elite tracking team from the Ugandan military that's searching for Kony in some of the most remote jungle on Earth.
You don't have to spend much time here to understand why it's so hard to find Joseph Kony. It's as isolated and unforgiving as it gets. The undergrowth so thick, every step is a battle.
When our producer Jeff Newton joined this Ugandan "tracking team," they'd been searching for Kony and his army, called the Lord's Resistance Army, or LRA, for three months, tracking them the way you would an animal.
Lukumbo: Right now, we are searching for the enemy tracks.
Jeff Newtown: Footprints?
Lukumbo: Yes, the footmarks of the LRA.
Twenty-seven-year-old Lt. Kasim Lukumbo's sole mission for the past three years has been finding Kony and he's one of the Ugandan army's top trackers.
The footprints are the first sign they've seen of Kony's army in six days.
As they followed the trail, the soldiers whispered so as not to give away their positions.
After an hour they reached this stream, but the tracks disappeared into the water.
Jeff Newton: No LRA?
Ugandan soldier: "No LRA. Let's go back."
There were no Green Berets on this mission. They do go out on operations like this, but they prefer to stay in the background. Keeping a low profile is part of the U.S. strategy.
Kurt Crytzer: They're the lead. They've always been the lead. We're relatively new here. We've only been here just about a year. It's really an African problem. It's being handled by Africans.
Col. Kurt Crytzer, a veteran Green Beret of 23 years, flew with us over the seemingly endless jungle, where the area they're searching is as big as Texas.
He took command of the U.S. Special Operations mission here not long after President Obama decided to send in troops 18 months ago.
Kurt Crytzer: The environment is some of the most unforgiving on planet Earth. When you get to the jungle, 50 feet in you disappear.
Lara Logan: You're like a ghost.
Video courtesy of Ugandan Defense Press Unit, Republic of Uganda, ITN Source and Media Africa