The Hmong were recruited by the CIA to fight a secret war in the jungle [Photo: Tony Birtley]

Al Jazeera's correspondent Tony Birtley travelled in secret to the jungles of northern Laos in search of the last fighters of the CIA's "secret army", a remnant from the days of the Vietnam War. This is his account of his journey.

I couldn't see the faces of my guides, but I could see their guns and I could feel the apprehension as they ushered me into the undergrowth and the start of what would turn out to be an unforgettable journey.

There were six of them, all ethnic Hmong; a rugged, tough people used to harsh conditions. But a people, I was soon to discover, living in fear.

We hurried into the forest - not easy in the dark - down a steep slope, across a narrow bamboo bridge over a fast-flowing river, and then upwards.

When we talked it was in a whisper; when we walked we tried not to create noise. And we tried to avoid the danger, which they told me was all around.

The danger comes from the Laos army. They are everywhere, the guides told me and ambushes are common.

In the dark, with the occasional use of a torch, we weaved our way through the undergrowth.

The "food" was a plant root similar to a yam, tasting like dried potato [Photo: Tony Birtley]

The darkness creates fear and apprehension but it is also strangely comforting: if you cannot see the soldiers, then it is equally hard for them to see you.

The first five hours was straight up, no deviations, and no track. Sometimes clambering for something to hold and pull myself up, other times it was all I could do to stop from falling backwards.

No such exhaustion for the Hmong; this kind of hike was normal in this hilly highland terrain of northern Laos.

Five hours and numerous stops later we reached the peak of the hill and a chance to sleep for a few hours.

We walked for another two hours beneath the dense jungle canopy, then stopped for food.

The "food" was a plant root similar to a yam, tasting like dried potato and something I came to dread in the coming days.

Men, women and children were on their knees, hands together as in prayer. And there were tears, floods of tears.

A Hmong man with a video camera filmed me. A woman dressed in traditional colourful Hmong clothes paused her sobbing and looked at me.

"Oh father, we are just widows. Our husbands, wives and children are lost. We are poverty stricken, please help us. We have no one to guide us," she said.

Everyone was shouting out. Four young men were performing a welcome dance. A young fighter, grenade launcher on his back, grenades around his waste, played an out of tune guitar.