Indonesian police have detained hundreds of pro-independence demonstrators in the eastern province of Papua on the anniversary of Dutch New Guinea's 1963 integration into Indonesia.
About 500 people were detained in the provincial capital, Jayapura, police said, and dozens in other cities of the resource province of around 3.5 million. There were no reports of violence.
"In spirit they support Papua's separation from Indonesia," said Papua police spokesman Patridge Renwarin.
"We are trying to explain to them that this goes against the spirit of the unitary state of Indonesia."
Papuan activist Markus Haluk told Reuters demonstrators had voiced support for calls for an internationally monitored referendum for independence.
Papua has seen a long-running and often violent separatist conflict since being incorporated into Indonesia after a widely criticised UN-backed referendum in 1969. Dutch colonial rule ended in 1963.
Indonesian President Joko Widodo has made several trips to Papua since taking office in 2014 and has promised to bring development to the impoverished region after decades of neglect.
His government has also released several political prisoners and pledged to resolve cases of human rights violations.
But security forces still maintain a strong presence in the restive region and are often seen as taking a heavy-handed approach to peaceful demonstrations, activists say.
Papua province and West Papua make up the western half of the island, with independent Papua New Guinea to the east.