Sirojiddin Bakhodirov was arrested this week with small amounts of marijuana and crystal meth.
Today a Bangkok court extended the Uzbeck national's remand, according to police.
But Bakhodirov, who is the only Uighur translator at the Bangkok bomb trial, told AFP by phone the drugs were planted on him as punishment for helping Thailand's Uighur community.
The mostly Muslim ethnic minority faces persecution and discrimination in their homeland in northwestern China, forcing many to flee and often use Thailand as a transit country.
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"I am innocent, they set me up," Bakhodirov told AFP of his drug charges.
"They don't want me to translate because I help the Uighur community".
Police have denied the framing allegations.
"It happens to be that (the suspect) is related to a high-profile case. That is why it is getting attention from the public," said deputy police spokesman Krissana Pattanacharoen.
Bakhodirov told AFP army officers interrogated him about Uighurs in other parts of Thailand after his arrest.