Singaporeans have been urged by Prime Minister Lee Hsien Loong not to "tarnish" their view of migrants, following a rare riot sparked by the death of an Indian national.
He said "the vast majority of foreign workers" in Singapore were law-abiding.
Police arrested 27 people, mostly Indian nationals, after hundreds rioted on Sunday in the Little India district.
Trouble started after the 33-year-old man was knocked down and killed by a private bus.
About 400 foreign workers took to the streets, throwing railings at police, and setting alight police cars and an ambulance.
Rioting in Singapore is punishable by up to seven years in prison plus caning.
At least 18 people were hurt, most of them police officers, before the violence was brought under control.
Mr Lee said on Facebook that people should not to react negatively towards migrant workers in Singapore.
"They contribute to our economy, working hard to earn a living and support their families back home," he said.
"We must not let this bad incident tarnish our views of workers here. Nor should we condone hateful or xenophobic comments, especially online.''
Mr Lee said he had ordered an inquiry into the riot to "look into the factors that led to the incident and how the incident was handled on the ground".
"It will also review the current measures to manage areas where foreign workers congregate, whether they are adequate and how they can be improved," he said.
In an earlier message he had stressed that "whatever events may have sparked the rioting, there is no excuse for such violent, destructive, and criminal behaviour".
"We will spare no effort to identify the culprits and deal with them with the full force of the law."
Police commissioner Ng Joo Hee said it was the first rioting in Singapore in more than 30 years. He condemned it as "intolerable, wanton violence" and said it was "not the Singapore way".
Singapore depends heavily on foreign workers, with migrant labourers from South Asia dominating sectors like building.
Most are young men who come from India and Bangladesh, and live in dormitories while they work and send money home.
The Indian High Commission said in a statement that it was "in constant touch with the Singapore authorities" and would "provide all assistance to affected Indian nationals".
"We hope all parties will maintain calm," it added.
Pictures and videos posted in social media showed two police cars being overturned by the mob. Several private vehicles were also damaged.
Singapore's Civil Defence Force (SCDF) said in a statement that rescuers went to the scene on Sunday and found a man trapped under a bus.
"An SCDF paramedic pronounced him dead on arrival. SCDF rescuers extricated the body using hydraulic rescue equipment," said the statement.
"Projectiles were thrown at the SCDF rescuers while they were extricating the body."
Nine SCDF vehicles were damaged in the incident, including five which were burned, it said.