Apriadi Gunawan, Medan – The Humbang Hasundutan Police on Tuesday detained 31 people involved in vandalism during a clash with PT Toba Pulp Lestari (TPL) security guards in an incense forest in Pollung district, Humbang Hasundutan, North Sumatra.

Humbang Hasundutan Police chief Adj. Sr. Comr. Heri Sulismono said 16 of the 31 detainees had been named as suspects. He added that the suspects were directly involved in the clash with the security guards.

"The 16 suspects were caught carrying sharp weapons during the clash. They also vandalized and set fire to a truck owned by TPL," Heri told The Jakarta Post on Tuesday.

Hundreds of residents from Pandumaan and Sipituhuta villages were involved in a clash with TPL security guards in the incense forest in Pollung district on Sunday. No casualties were reported in the clash.

The next day, the police arrested 16 residents involved in the clash. The police continued to arrest residents until early Tuesday, and arrested 15 more people, who Heri said were witnesses.

Delima Silalahi, the coordinator of a team providing advocacy to the residents, filed a complaint with the police on account of its alleged brutal treatment of residents. Delima said the 15 residents were forcefully taken from their homes as while they were asleep.

She said the conflict between residents and TPL had been going on since 2009 over the status of local customary land, which TPL claimed as part of its assets.

The disputed customary land, more than 4,000 hectares, had been declared as status quo by the National Commission on Human Rights in 2010 and strengthened by a local consultative forum in 2011. However, TPL has continued to operate there.

TPL spokesman Chairuddin Pasaribu said the disputed land was actually part of TPL's concession land that had been granted by the government through the Forestry Ministerial Decree No. 493/KPPS-II/92 dated June 1, 1992.

"The concession land given by the government measures 269,060 ha," he said. He claimed that Sunday's clash had stemmed from the continued efforts of locals to prevent TPL from harvesting eucalyptus trees on its concession land.