KUALA LUMPUR (AFP) - A helicopter and over 150 people were deployed on Tuesday (Aug 6) on the third day of a search for a vulnerable London teenager who went missing from a Malaysian rainforest resort, police said.

Nora Quoirin, 15, disappeared on Sunday morning, a day after checking into the Dusun Resort, about an hour from the capital Kuala Lumpur.

The teen, who has learning difficulties, lives in London and is the daughter of a Franco-Irish couple.

The helicopter and 178 people from various government agencies searched for her in the jungles near the resort, said senior police official Mohamad Mat Yusop.

"We will do our best and will not give up hope," he told reporters. "We feel she did not go far."

Police have classified her disappearance as a missing person case and are not treating it as an abduction.

But the girl's family have told the Lucie Blackman Trust, a British charity that supports the families of British people who go missing abroad, that they suspect foul play.

The Dusun is a five-hectare resort in the foothills of a mountain range and next to a forest reserve.

On Sunday morning, the teen's parents found their daughter's bedroom empty and the window open, according to one of her French relatives.

The resort's management said in a Facebook post that its employees were "extremely distressed and worried" about her disappearance and were assisting in the search.