Fresh charges were handed out to four of the 25 people charged in the Little India riot of Dec 8 on Friday.
The additional charges were against Chinnappa Prabakaran, 23, who was charged with instigating a group of male Indians to set fire to an ambulance; and Bose Prabakar, 29, who was accused of assaulting an auxiliary police officer by kicking him.
Moorthy Kabildev, 24, also faces an additional charge of punching bus coordinator Madam Wong Geck Woon inside the bus which ran over Mr Sakthivel Kumaravelu, 33, an Indian national construction worker.
The accident sparked the riot, the first in more than 40 years here.
Arumugam Karthik, 24, now also faces two new charges: one of setting fire to a police car with one other person; and one of throwing pieces of concrete and flipping over a police car with some others.
The Straits Times understands that prosecution is looking to revoke their bail, or increase their bail to between $40,000 and $60,000.
Since bail was granted to all 25 accused on Tuesday, only one has posted bail - Arun Kaliamurthy 28, who was in Singapore on a social visit pass. The bail was set at $20,000 and the money must be paid in cash by a Singaporean bailor.
On Friday, the court allowed Chinnathambi Malesan's employer to post bail, even though the employer, Mr Lew Kok Leong, is a Malaysian.
The accused's lawyer had argued that Mr Lew has sunk roots in Singapore: he has been a permanent resident since 1978, owns an HDB property and runs his construction firm here with a partner.