Military spokesman Brigadier General Restituto Padilla described the fight on the eve of the Muslim holiday of Eid al-Adha as some of the toughest fighting yet.
Dr Norhizan Ismail, the state Health director, says that the boy is being treated at the Paediatric Intensive Care Unit of the Sultanah Bahiyah Hospital for serious head injuries.
The Agri-Food and Veterinary Authority says that it is investigating the case of alleged smuggle of illegal wildlife products through the country along with Singapore Customs and the Immigration and Checkpoints Authority (ICA).
Reports said that Tan also pleaded guilty to an unrelated charge of receiving stolen property of S$6,950 from anonymous sources linked to a police impersonation scam.
If convicted, a person who knowingly lives on the earnings of the prostitution of another person can be jailed up to five years and fined up to S$10,000.