Papua New Guinea kidnap: Archaeologist Bryce Barker and colleagues freed

Bryce Barker and his colleagues were on a field study trip near Mount Bosavi when they were taken hostage

An archaeologist and two of his colleagues have been rescued after being held captive for a week by an armed group in Papua New Guinea (PNG).

Professor Bryce Barker, a New Zealand citizen who lives in Australia, was originally captured at gunpoint with three colleagues as they took part in a field study trip near Mount Bosavi.

One of the group was freed on Thursday.

PNG's leader has said the group was released without paying the ransom that had been demanded.

Prime Minister James Marape said the kidnappers wanted 3.5m Papua New Guinean Kina ($994,000; £832,000) but the hostages had been rescued "through covert operations".

"We apologise to the families of those taken as hostages for ransom," he said. "To criminals, there is no profit in crime. We thank God that life was protected."

PNG's prime minister says Bryce Barker and his colleagues were released without a ransom being paid

The Australian Broadcasting Corporation (ABC) named the women who were held with Professor Barker as Jemina Haro, Teppsy Beni and Cathy Alex - all members of his research team.

Professor Barker works for the University of Southern Queensland and the university's Vice-Chancellor Geraldine Mackenzie said they were relieved he was safe.

She described the professor as a "highly regarded archaeologist and a valued colleague" with many years experience of research in the region.

New Zealand's foreign minister, Nanaia Mahuta, wrote on social media that her country "welcomes the safe release of hostages in PNG including a NZer".

"Tenkiu tru for your leadership and cooperation governments of PNG and Australia," she added, using the phrase from the creole Tok Pisin or Pidgin language used in PNG that means "thank-you very much".

Penny Wong, Australia's foreign minister, has also thanks the PNG government for "its leadership in securing a safe & peaceful resolution".

Philip Mehrtens with TPNPB fighters in video footage sent to the BBC

Unrest in Papua

In neighbouring Papua, which is controlled by Indonesia, it is understood New Zealand pilot Philip Mehrtens is still being held captive.

He was kidnapped more than two weeks ago after landing his plane in Papua's remote mountainous province of Nduga.

The West Papua National Liberation Army (TPNPB), a rebel group that rejects Indonesian rule, has pledged to release Mr Mehrtens if Papua is granted independence.

Separately, Indonesian officials said on Friday that they had tightened security in the town of Wamena in the country's eastern region after 10 people were killed during a riot sparked by rumours that a child had been abducted.

Security forces reportedly opened fire on locals after suspicion that the authorities were holding the person responsible for the suspected abduction led people to attack a police station and other buildings.