Police in Solomon Islands say a group of Bougainvilleans who escaped from custody last week were arrested because they were deemed a security risk.
The 29 men were apprehended at sea last week travelling in three boats.
Police said the men were armed and on their way to the Western Provincial capital Gizo to seek compensation for the death of a relative earlier this month.
The police feared trouble if their demands for compensation were not met.
The men escaped from police custody on Wednesday last week after being suspected of entering the country illegally.
By Saturday, nine of the men had turned themselves in.
Police said they had been interviewed and processed by police and immigration officers and escorted back over the Solomon Islands-Papua New Guinea border.
Criticism of the arrests
Because of close family ties between Papua New Guinea's Bougainville and the Solomons' Shortland Islands, communities there are allowed to travel freely between the two regions.
There has been criticism that the arrests were insensitive and might have repercussions for Solomon Islanders living in or travelling to Bougainville.
The Solomon Islands Police Commissioner Matthew Varley said such fears were unfounded and clarified that the special customary travel zone between Bougainville and Western Province only applied to the Shortland Islands.
There was no automatic immigration approval for foreign citizens to travel beyond the Shortland Islands, he said.
The police chief said throughout the operation Solomon Islands police were in daily contact with their counterparts on Bougainville.
He called on communities on both sides of the border to respect the laws of both countries.
Increased police presence in Western Province
Solomon Islands police said they would continue to maintain a high visibility presence in Gizo and surrounding islands over the coming days.
They will also continue to investigate the lapse in security which led to the escape of the men from Gizo Police Station on the morning of February 21.
Police are also warning anyone assisting the 20 Bougainvilleans still at large that it is unlawful to harbour and assist anyone who has escaped from custody.