Singapore's Central Narcotics Bureau (CNB) conducted the raid with the support of the Singapore Civil Defence Force (SCDF) and the Health Sciences Authority (HSA).
Minister for Home Affairs K Shanmugam has warned against religious preachers who he said are propagating radical thoughts and divisive teachings in Singapore.
Thundery showers are expected mainly over northern, eastern and the western zones and NEA have further issued warnings of thundershowers in the early afternoon for tomorrow.
Singapore Central Police Division nabbed 26 women, aged between 24 and 40, during a police raid in seven unlicensed massage parlours in Jalan Besar, Lavender and Little India.