Indonesian villagers have trapped and killed their fourth endangered Sumatran tiger amid a flurry of tiger attacks blamed on illegal logging, the environmental group World Wildlife Fund said on Friday.

Four tigers and six people, it said, have been killed on the island of Sumatra this month.

"We learned on Feb. 24 that another Sumatran tiger had been trapped and killed by villagers after it attacked two farmers on Sunday," said Syamsidar, a WWF spokeswoman.

"This is the fourth tiger killed this month and we are concerned because it is a protected animal and an endangered species."

Syamsidar said the two farmers, from Simpang Gaung village in Riau Province, were seriously injured in the attack. "The tiger in the latest killing had wandered into the village after its habitat had been destroyed by people," she said.

The Detikcom news portal reported that MS Kaban, the minister of forestry, had urged the provincial police to arrest the tiger killers. "They can't kill these tigers as they please," he said. "Whatever their excuse, the tigers must be protected."

According to WWF, there are fewer than 400 Sumatran tigers left in the wild and their increasing contact with people is a result of habitat loss and continuing deforestation.

The nongovernmental organization said about 12 million hectares of forest on Sumatra had been cleared in the past 22 years, which equated to a loss of nearly 50 percent of the island's forests. The incidents in Riau occurred in an area dotted with pulp and palm oil plantations. This intense deforestation has left Sumatra's wildlife – tigers, orangutans, elephants and rhinos – with little room to move.

Krystof Obidzinski of the Center for International Forestry Research said a lot of Indonesians got into the black market timber business during the 1997-98 Asian financial crisis. "Significant numbers of people are being put out of work already, so we will have to wait and see what impact that will have for illegal logging," he said.