Tuesday's protest had been held to encourage lawmakers to approve a motion that would lead to substantive constitutional change, including measures to limit the power of the monarchy.
Sucharn Thoumrungroje, a 20-year-old engineering student, said he decided to attend Wednesday's rally after learning of what happened at Parliament the day before. That motion, submitted by iLaw, the Internet Law Reform Dialogue, would have allowed all aspects of the constitution to be changed, including articles dealing with the monarchy.
According to Erawan emergency services, 55 people at Tuesday's protest were sent to hospitals, the largest number suffering from the effects of tear gas. It said four remained hospitalized Wednesday, including three of the six people it said had suffered gunshot wounds. The circumstances of the shootings were not announced.
"We are in the process of an investigation into who might be behind the shootings," said police deputy spokesperson Col. Kissana Phathanacharoen. "No rubber or live bullets were used by the police for yesterday's police operation, that is confirmed."