DILI, East Timor (AFP) - An American woman is being held in East Timor after her arrest two months ago following the discovery of drugs in a taxi that she was sharing, her lawyer said on Wednesday.

Tourist Stacey Addison has denied any wrongdoing following her arrest on Sept 5 after methamphetamine was found in the shared taxi that was en route to the capital Dili.

The vet, who had just crossed from Indonesia when she was arrested, wrote on Facebook that another passenger - who was a stranger - picked up a package containing the drugs, and the police later detained everyone in the car. She was initially released from jail after several days, but her passport was confiscated pending further investigation.

However, at a hearing on Octr 29 to get her passport back, she was rearrested and has been sent back to prison, although no charges have yet been laid against her, the US State Department said.

"PLEASE HELP!" she wrote in a Facebook post two weeks after her initial arrest.

"My bags were searched, my body was searched, all medications I am carrying were tested, and my urine was tested."

All the tests came back negative, she added. After her conditional release, Addison said that she had been informed an investigation into the case would likely take a year.

Her lawyer Paulo Remedios in East Timor confirmed the details, telling AFP: "She was believed to have violated anti-narcotics laws as police found narcotics in a car she was sharing with another passenger and a driver."

The East Timor police refused to comment.

State Department spokesman Jen Psaki told reporters in Washington that a senior US official met with East Timor's ambassador last week and raised concerns about the case.

"We have significant concerns about this case which we have expressed," she said.

She said the official also expressed "our hope for a prompt and transparent resolution to the case".

East Timor, a poor half-island nation that was occupied by Indonesia for over two decades, imposes tough punishments for drugs cases, including the death penalty for traffickers.