Five Indonesian men remained trapped up a tree Sunday three days after being chased into its branches by Sumatran tigers who also mauled their friend to death, police said.

Four of the snarling animals were still surrounding the base of the tree following their initial attack on Thursday, which they launched after the men accidentally killed a tiger cub.

Humans and animals are increasingly coming into conflict in Indonesia -- but in most cases, it is the animals who end up the losers.

The men entered the Mount Leuser National Park in the north of Sumatra island on Tuesday searching for rare incense wood, district police chief Dicky Sondani told AFP.

"The wood is very expensive... but they run a risk looking for it as they have to go to more remote parts of Leuser where there are many tigers and elephants," he said.

The men set up traps for deers and antelopes for food -- but accidentally trapped and killed the tiger cub.

The adult tigers reacted by attacking the men. They killed a 28-year-old identified only as David, but the five others took refuge up a tree, Sondani said.

"Four tigers are still surrounding the men under the tree," he added.

Thirty rescuers including police and soldiers set out on Saturday to rescue the men after villagers who tried to help them turned back after seeing the tigers.

But the rescuers would take two to three days to reach the men, Sondani added.

"If the tigers remain under the tree, we may have to shoot or sedate them to rescue the five people," he added.

The Leuser ecosystem is home to around 5,800 of the remaining 6,600 critically endangered Sumatran orangutans as well as elephants and tigers, but it is threatened by commercial logging and clearance for palm oil plantations.

The Sumatran tiger is the world's smallest tiger. There are only an estimated 400 to 500 still alive in the wild.