Nine trafficked orangutans were flown back home to western Indonesia on Friday after the primates were rescued from the illicit wildlife trade in Malaysia.

Poachers in Southeast Asia frequently capture the critically endangered Sumatran orangutans to sell as pets, and fewer than 15,000 of the apes are estimated to remain in the wild. 

The group were flown to North Sumatra province on Friday, a day after arriving in Indonesia from a wildlife rescue centre in Malaysia that was caring for the creatures. 

Provincial conservation official Hotmauli Sianturi told a press conference on Friday that the apes had been tested and cleared for Covid-19 infections. 

They will now be taken to a sanctuary to undergo observation for a few months before they are returned to the forest. 

Their arrival in Indonesia came the same day as another pair of orangutans were flown back to the country from a wildlife breeding centre in Thailand.

Traffickers had attempted to smuggle them into Thailand through Malaysia three years ago but were intercepted by local authorities at the border.

Sumatran orangutans' habitat has drastically shrunk over the past few decades from logging, palm oil plantations and mining.

Plantation workers and villagers sometimes attack the animals for being pests.