Jakarta  - Activists of the environmental pressure group Greenpeace were beaten by security guards while protesting against environmental destruction outside the headquarters of one of Indonesia's largest palm oil companies Thursday, the group said.

Greenpeace accused the Sinar Mas Group, whose businesses include pulp, paper and palm oil, of destroying Indonesia's forests with impunity through its operations on Sumatra Island, the Indonesian part of Borneo and Papua.

Greenpeace said in a statement that company security guards kicked and punched the activists as climbers unfurled a huge banner branding Sinar Mas a "Forest and Climate Criminal."

"The excessive violence today by Sinar Mas security is testament to the way this company does business," said Greenpeace forest campaigner Bustar Maitar.

"We are facing the greatest threat to humanity - climate chaos, yet still companies like Sinar Mas continue to destroy forests and peatlands, rather than protecting them for future generations and, as is becoming increasingly clear, for climate stability" he said.

Sinar Mas officials could no be reached for comment.

The company is also poised for massive expansion as they hold unplanted concession areas totalling another 200,000 hectares of Indonesian rainforest and have plans to acquire a further 1.1 million hectares, mainly in Papua, the environmentalists said.

Greenpeace urged the Indonesian government to implement a moratorium on any further forest conversion.

Indonesia is regarded as the third-largest greenhouse gas emitter after the United States and China, largely due to the rapid destruction of its forests. (dpa)