US officials said it was a telecommunications outage and not a threat to the United States.

Federal Aviation Administration technicians are investigating the issue.

US Homeland Security chief Markwayne Mullin said there was no indication the country was under threat.

"This isn't another 9/11. I just can't repeat that enough."

But asked if a cyberattack could eventually be found to be responsible, Mullin said officials were "not ruling out anything at this point".

It has since worked with its return network operators to calibrate the machines to address the issue, and will continue to strengthen safeguards.

A TikTok user had posted the video showing the man using a single can to get the BCRS machine to accept other bottles and cans, along with the question" "Is this legal?"

Consumers can only receive a 10-cent refund by returning containers with a 10-cent deposit mark at Return Right reverse vending machines. The cans and bottles the man was returning were ineligible.

BCRS Ltd says its machines have digital transaction logs and 24-hour CCTV surveillance.

The death follows a fatal accident involving a 37-year-old female cyclist and a tipper truck on Wednesday at the junction of Amber Road and Amber Gardens. Earlier that day, a 52-year-old male cyclist was taken to hospital after an accident with a taxi at the junction of Kaki Bukit Avenue 2 and Eunos Link.