I watched a film around 2005 that involved modern soldiers (possibly American) who are being stalked and killed one by one in a forest or jungle. The look and feel is similar to Predator - big GI's with vests, bulging muscles and heavy weaponry. However, it's not a humanoid they are fighting but a sort of infestation of large vines that attack by wrapping around victims and sucking all the fluid out them - leaving sort of emaciated and discoloured husks.
The soldiers stumble across a few 'dehydrated' bodies that confuses and terrifies everyone ("What the hell could have done that!?" etc), and the threat is later revealed where you see a soldier killed gruesomely in front of everyone - I'm sure there is a moment where he is trapped and people try to rescue him, but as they get close he dies horribly. I was quite young and the imagery has stuck with me for a long time - it was quite dramatic in that creepy bad visual effects way like the end of Raiders Of The Lost Ark.
I distinctly remember a scene where a soldier successfully blows up a bunch of the 'vines' with a grenade launcher - it might have been a rotating barrel grenade launcher or an under slung one on an M16 or similar.
The plot might have involved an abandoned research station where Bad Things Happened(TM) that led to the current events, but I might just be confusing similar plots now so I'm not sure about that point.
There may also have been a female researcher who acted as the foil to all the big muscly soldier types and who was interested in studying and finding out what was going on rather than just blowing everything up.
I watched this late at night on a Sky box with hundreds of channels - it could have been anywhere to be honest.
I'm unsure how old the film was but at the time I thought it was likely from the 90s. It may have been a feature film, a straight to TV film or part of a series I was unfamiliar with.