About 400 South Asian migrant workers angered by a road accident battled police and set vehicles ablaze in Singapore's worst rioting in decades, leaving 18 people injured, officials said Monday.

The violence erupted in the city-state's crowded Little India neighborhood Sunday night after an Indian worker was hit and killed by a private bus driven by a Singaporean, police and government authorities told a news conference.

Police arrested 27 South Asians, some of whom hurled bottles and other projectiles at authorities who tried to calm the scene, said police Commissioner Ng Joo Hee. Those hurt included 10 police officers and four defense force personnel.

Channel News Asia showed images of burning vehicles, a police car flipped on its side and people attacking the windshield of a bus with sticks and garbage bins. It said this was the worst such unrest in more than 40 years in Singapore, an orderly and modern city-state known for strict punishments and generally law-abiding citizens.

Prime Minister Lee Hsien Loong warned that authorities would ``spare no effort to identify the culprits and deal with them with the full force of the law.''

``Whatever events may have sparked the rioting, there is no excuse for such violent, destructive, and criminal behavior,'' Lee wrote in a statement on his Facebook page early Monday.

The violence sparked debate among Singaporeans on social media about issues of overcrowding and the increase of migrant workers hired for Singapore's construction sector and menial jobs.

Little India is an area popular among Indian, Bangladeshi, Pakistani, Sri Lankan and Nepali expatriates. It has scores of restaurants, grocery shops and a mall selling food and other items for people from those countries. On Sundays, the area is especially crowded with South Asian workers. (AP)