A section of the Prime Minister's Office (PMO) website was hacked into late Thursday night.
The Infocomm Development Authority of Singapore (IDA) said in a statement at about 1.30am on Friday that "a subpage for search on the PMO website was reported to be compromised" on Thursday at 11.17pm.
"A vulnerability in that subpage was exploited to display pages from other sources. This vulnerability is known as cross-site scripting," said the IDA. "The PMO main website is still working, and we are working to restore the page that has been compromised. The matter is under investigation."
This latest cyber intrusion comes after hacktivists threatened to cripple Singapore's information technology infrastructure last week. On Wednesday, Prime Minister Lee Hsien Loong issued a warning, saying that the authorities will "spare no effort" to track down those who threaten to attack the country's computer networks and bring them to justice.