Singapore Civil Defence Force (SCDF) officers had to force their way into Admiralty Primary School after a fire broke out in a toilet early yesterday morning.
Nobody was injured and there were no evacuations from the site, according to an SCDF spokesman.
The SCDF was alerted to the fire by a call received at 2.05am yesterday.
Firefighters entered the school premises at 11 Woodlands Circle using "forcible entry tools" and extinguished the fire with a water jet.
SCDF did not provide more details on how its officers entered the school premises.
News of the fire first started circulating on social media, with Twitter user Aticat (@AHteacar) posting a photo of the blaze from afar.
Videos of the fire were also uploaded on to YouTube and Twitter by users gunjr jr and Md Haziq Sasman (@peoplecallmeZiq) respectively.
The school is closed as it is Primary School Leaving Examination (PSLE) marking week.
Its vice-principal, Mr Jay Mahardale, told The Straits Times yesterday that the toilet was an unused one.
The cause of the fire is still under investigation.