
The three, Veera Musigapong, Natthawut Saikua and Weng Tojirakan, surrendered themselves to police on April 14 following the dispersal of the red-shirt crowd at Government House.
"The extension of custody is deemed necessary under emergency rule as a precaution against recurring disturbances if the three were to be granted bail," the court said in its ruling.
The red-shirt crowd disbanded after riots erupted around the capital. Under emergency rule, police have the mandate to detain suspects for seven days instead of 48 hours before the mandatory bail hearing by the judiciary.
In applying for temporary release, the defence argued that the state of emergency was wrongfully enforced.
But the court struck down the defence argument on the ground that there was no judicial review disputing the government's mandate for emergency rule.
Throughout the bail hearing, the three suspects appeared cheerful and were seen talking amicably among themselves and with the defence lawyers.
The next bail hearing is scheduled for April 29. The three are being detained at the headquarters of Border Patrol Police in Pathum Thani.
In regard to the legality related to the state of emergency, the court has scheduled today to launch a separate hearing.
The defence contends that Prime Minister Abhisit Vejjajiva imposed the emergency rule on April 12 without seeking a prior approval from the Cabinet.
In the today's judicial hearing, Cabinet secretary general Surachai Phuprasert and relevant officials will testify about steps taken to declare the state of emergency.