Watch video of tiger cubs playing in the forest here

JAKARTA (AFP) – Conservation group WWF on Monday urged timber firms to drop plans to clear Indonesian forest areas where infra-red cameras have captured footage of rare Sumatran tigers and their cubs.

The video, recorded in March and April, shows two mothers with four cubs and another six of the critically endangered big cats in the Bukit Tigapuluh wildlife reserve in eastern Sumatra.

"That was the highest number of tigers and tiger images obtained... we've ever experienced," WWF tiger researcher Karmila Parakkasi said in a statement.

The WWF said the 12 tigers were concentrated in locations with good forest cover, including in a land concession belonging to Barito Pacific Timber, which it described as a wood supplier to regional giant Asia Pulp and Paper (APP).

"This video confirms the extreme importance of these forests in the Bukit Tigapuluh ecosystem and its wildlife corridor," the WWF's forest and species programme director Anwar Purwoto said.

"WWF calls for all concessions operating in this area to abandon plans to clear this forest and protect areas with high conservation value," he added, urging authorities to manage the zone "as part of Indonesia's commitments to protecting biodiversity".

There are fewer than 400 Sumatran tigers left in the wild, among a global tiger population of just 3,200 -- down from 100,000 a century ago.

WWF spokeswoman Desmarita Murni said that Jakarta designated the Bukit Tigapuluh area as one of six priority tiger conservation zones during last year's Tiger Summit in Russia.

"They have to ensure that its commitment is well implemented," she told AFP.

APP denied WWF's claims that Barito Pacific Timber is its subsidiary or supplier. "It's not related whatsoever with our group," a spokeswoman said.

Barito Pacific Timber could not be reached for comment.

Environmental activists say that Sumatran tigers are increasingly coming into contact with people as a result of their natural habitat being lost due to deforestation for timber and palm oil plantations.

President Susilo Bambang Yudhoyono has been under pressure from environmentalists to implement a promised two-year moratorium on the clearing of natural forest and peatland, which was due to begin January 1.

Norway agreed in May last year to contribute up to $1 billion to help preserve Indonesia's forests, in part through the moratorium.

WWF warned last year, during the Year of the Tiger, that the species is on course for outright extinction by 2022 -- the next Year of the Tiger under the Chinese calendar.

Thirteen countries host fragile tiger populations -- Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Russia, Thailand and Vietnam.

Russia is the only country to have seen its tiger population rise in recent years. It had just 80 to 100 in the 1960s but now has around 500 -- raising hopes that the majestic creature can be saved if decisive action is taken.