SINGAPORE - The National Environment Agency (NEA) is investigating an alleged incident of curry being dumped into a river.

In response to queries from The Straits Times, NEA said in a statement that it had received reports, along with water agency PUB, on Sunday (Feb 4) about "a substance resembling curry being disposed into Sungei Tampines".

"NEA and PUB officers went down to the site immediately, and NEA is investigating the alleged incident," said the statement.

Facebook user Shirley Lc Tan had posted a photo of the orange substance seeping into the river at 9.35pm on Sunday.

She alleged that the caterer of a wedding held at the void deck of Block 408, Pasir Ris Drive 6, had dumped their curry gravy into the river next to it.

"The river where there are plenty of monitor lizards and our beloved Pasir Ris family of otters," she wrote.

The post drew more than 2,400 shares and hundreds of likes and comments. It was made unavailable on Monday night.

Sungei Tampines flows through parts of Tampines and Pasir Ris before draining into the sea.

An otter watcher told ST that he saw the otters in Sungei Tampines on Saturday morning. They left the river and headed for Sungei Api Api, a river in Pasir Ris, said Mr Tan Yong Lin, a 28-year-old professional photographer.

Mr Tan, who has followed otters for about two years, said the otters were out of the water by the time the curry incident happened.

However, he added that another otter watcher went to look for the animals earlier on Monday, but she did not see them at Sungei Tampines.