JAKARTA (Reuters) - Six hundred Indonesian soldiers will finish building a highway in the province of Papua, a military spokesman said on Tuesday, after 16 construction workers were killed by separatists in the restive area last year.

The soldiers working on the Trans-Papua highway and 21 bridges will continue security operations in the area home to a simmering separatist conflict since Papua was incorporated into Indonesia in 1969.

“They will build the road because conditions in the field are difficult and there are disruptions from armed criminal groups,” military spokesman Brigadier General Sisriadi said via text message.

Construction on parts of the 4,300 km (2,672 miles) highway has been stalled for months after the military wing of the Free Papua Movement (OPM) claimed responsibility for killing at least 16 workers and a soldier in Nduga district in December.

Fighting between rebels and the Indonesian military caused hundreds of villagers to flee the resource-rich area in western New Guinea island.

President Joko Widodo, who faces an election in April, vowed to finish the highway project as part of his promise to develop Papua, Indonesia’s poorest region.

But he faces criticism from rights activists for not doing enough to investigate accusations of rights abuses by security forces there.

United Nations rights experts last month urged Indonesia to investigate accusations of violence by police and military in Papua after a video showed officers using a live snake to intimidate a suspect during questioning.