Ousted Thai Prime Minister Thaksin Shinawatra pleaded not guilty Wednesday before the Supreme Court in one of two criminal corruption cases against him.

More than 200 policemen with bomb detectors and five sniffer dogs were deployed around the court where some 400 of Thaksin's supporters waited, many holding portraits of the former leader over their heads.

"The defendant pleaded not guilty of the charges," chief judge Thongloh Chom-ngam told the court, which set the next hearing for April 29. It also excused Thaksin from having to appear at every hearing, as requested by his lawyer.

"We can prove our innocence," said Thaksin, who was ousted in a September 2006 military coup for alleged corruption and abuse of power.