SINGAPORE — Staff at the Environment Building on Scotts Road were evacuated on Wednesday (Aug 23) morning following a "security situation" that prompted a lockdown.

The building houses the Ministry of Sustainability and the Environment (MSE) and its statutory boards the National Environment Agency and water agency PUB.

In a Facebook post on Wednesday, Minister for Sustainability and the Environment Grace Fu said that the police had worked with security offices on the premises to conduct preliminary checks and "no threat items were found".

Ms Fu added that she found out about the situation while attending Association of Southeast Asian Nations meetings in Vientiane, Laos.

“I’m monitoring the developments closely from here and am in constant contact with my colleagues,” she said.

“I would like to assure all staff and stakeholders at the Environment Building that their safety is our priority.”

TODAY understands the building was locked down at 9.30am. An email was sent to MSE staff at 10am stating that there was an "emergency situation" and that the building was "under lockdown".

Staff were told that they could leave the building and continue working from home.

It is understood that many staff were already working from home.

When TODAY arrived on the scene at about 11am, there were four police cars parked at a corner of the building.

Most staff exiting the building appeared to be calm and unhurried.

Some of the staff TODAY spoke to said they were unaware of the reason for the mass evacuation, while others did not know about the email and said they followed their colleagues out of the building.

TODAY also spoke to some stall owners at the cafeteria on the building's second floor. They said they were told by building management to halt dining-in services and only provide takeaway options.

The cafeteria is frequented by many office workers from surrounding buildings, and some were seen leaving the cafeteria with takeaway bags.

TODAY understands that a second email was later sent to MSE staff, stating that the building and the canteen will be closed for the rest of the week. 

This is a developing story.