Papuan independence fighters are vowing more attacks on a highway that's the Indonesian president's key development project in the troubled easternmost region.

The threat is made in a video purportedly recorded last week in the Nduga area of Papua province's central highlands. It shows about 40 fighters, a few with Indonesian military assault weapons.

In the video, a man standing next to a liberation army commander reads out a statement that taunts the military for being unable to find the Papuan fighters even though they're in the same mountainous area.

Indonesian forces have poured into Nduga since rebels killed 19 people working on the trans-Papua highway in December. The military says its engineers will build 21 bridges need to complete the highway.