MEDAN, INDONESIA - Two Indonesian journalists mediating a land dispute between a palm oil company and residents have been found dead with multiple stab wounds near a plantation in Sumatra, police said.

The body of Maraden Sianipar was found Wednesday in a ditch near a palm plantation in Labuhan Batu district, an eight-hour drive from the capital of North Sumatra province.

Police found the remains of Maratua Siregar in the same area a day later.

Both bodies were covered in stab wounds.

Six people have been questioned but no suspect named, local police chief Agus Darojat told AFP.

The pair worked together for a local news portal before going freelance in 2017, and a friend of Siregar said the victims had recently become known for their activism in land dispute issues.

Local police chief Budiarto told the Jakarta Post that investigators had found indications that the reporters' deaths were related to their activism.

Maratua "often advocated for the people", he told the newspaper.

Prior to their deaths, Siregar and Sianipar were working on a campaign to convince the government to allow locals to work on disputed land.

Indonesian journalist associations condemned the deaths and demanded authorities investigate thoroughly.

Many cases of violence against journalists in Indonesia go unsolved, according to the Independent Journalists Alliance, which has reported at least two dozen cases this year alone.

Indonesia is ranked 124th out of 180 countries on the 2019 World Press Freedom Index published by Reporters Without Borders.