A woman who was taken hostage in Papua New Guinea has been released while an Australian professor and two local researchers are still held captive by an armed group in the country’s remote highlands. The remaining three captives are believed to be in reasonable health, despite being held in difficult terrain. “The release of one female Papua New Guinean captive is a positive outcome, and negotiations continue for the safe release of the remaining two female Papua New Guineans and the male New Zealand citizen,” the commissioner of police, David Manning, said in a statement. It is believed that the university professor, who has New Zealand citizenship but is an Australian resident, was conducting studies near Mount Bosavi with University of Papua New Guinea graduates and guides when they were reportedly confronted by the armed kidnappers on Sunday. They moved the hostages between villages in the area, an assistant police commissioner for Western End, John Kale, told the ABC. He is concerned that the hostages could be moved again through villages and thick forest. The kidnappers demanded payment from the PNG and Australian governments. Manning described the gunmen as “opportunists” and the situation as “delicate”. Negotiations are under way “to seek a peaceful resolution”. But Manning has said the abductors will be met with a “swift security response” if anyone held captive is harmed. Failure to comply and resisting arrest “could cost these criminals their lives”. Missionaries have been working with police on the ground and have spoken to the professor via satellite phone, according to reports. “We are continuing to work to strengthen lines of communication, which remains a challenging aspect of this operation,” Manning said. He also warned social media users and administrators of social media platforms to refrain from posting false information about the security operation. This came after incorrect rumours claiming that foreign military personnel were involved in the operation began to circulate on social media. “The circulation of fake news can complicate security operations leading to tragic outcomes, and I call on people using social media and administrators to not post information that has not been verified by official sources.” Manning said the operation to release the captives was under the command of PNG police, alongside the the country’s defence force and domestic security agencies. “As one of the captives is a New Zealand citizen with Australian residency, the High Commissions of both countries continue to be briefed on the situation.”