On 1 December 2018, an armed group with ties to OPM kidnapped 25 civilian construction workers in Nduga regency, Papua. The following day, the group killed 19 of the workers and a soldier. One of construction workers had allegedly photographed the group raising the Morning Star flag at an independence celebration - considered illegal acts by Indonesian authorities. The construction workers were building a part of the Trans Papua highway that aims to connect remote communities in Papua. A few days after the incident, the OPM allegedly sent an open letter to Indonesian president Joko Widodo, demanding Papuan independence, rejecting central government infrastructure building projects, and demanding the right for foreign journalists and aid workers to enter Papua. In reprisals to obtain the massacred workers' bodies, the Indonesian military allegedly carried out airstrikes on at least four villages and used white phosphorus, a chemical weapon banned by numerous countries and international organizations. This was however denied by the Indonesian government.