Indonesia's military says three of its soldiers were killed by West Papua Liberation Army fighters on Thursday, with up to 10 rebels dying in the gunfire exchange.
It's the latest bout of violence to strike the troubled Highlands regency of Nduga, where the Liberation Army had been carrying out guerilla attacks.
Since December, dozens of people have died in escalating clashes in Nduga, causing hundreds of civilians to flee.
On Thursday, Indonesia's military said between 50 and 70 Liberation Army fighters descended on soldiers guarding the construction of a bridge in Yigi district.
Military spokesperson Colonel Muhammad Aidi said three members died before the military was able to drive the rebels back.
He said between seven and ten Liberation Army fighters were killed and the military recovered one body, with the Liberation Army recovering the rest in their retreat.
A Liberation Army spokesperson, Sebby Sambom, claims its fighters killed five soldiers and seized four weapons.
Mr Sambon said the violence on Thursday was sparked when Indonesian soldiers interrogated a local villager and then set fire to five houses.
A Major General with Indonesia's military, Yosua Pandit Sembiring, said the soldiers who died on Thursday were heroes who died preserving Indonesia's sovereignty.
"This also proves that it is the armed separatist group that has become a burden for the Papuan people," he said, in reference to the Liberation Army.
Bridge and road construction in Papua has been at the centre of clashes between the state and rebel fighters since December, when the Liberation Army massacred at least 16 Indonesian workers near Nduga.
In Yigi district, Liberation Army fighters were also responsible for setting fire to a digger owned by a state-owned construction company last week.
Mr Sambon claimed a gunfire exchange took place at the time with military and police personnel injured, which Indonesia's military has denied.