Singapore has suspended the use of video-conferencing tool Zoom by its teachers, after a “very serious incident” during a home-based lesson.

Singapore closed its schools on Wednesday in response to a rising number of coronavirus cases.

But one mother told local media that, during her daughter’s geography lesson, obscene images appeared on screen, before two men asked girls to “flash”.

Zoom told the BBC the company was “deeply upset” about the incidents.

Zoom recently changed its default settings for home-based learning, and issued a guide for teachers to secure their “virtual classrooms”.

What happened in the classroom?

Parents told local media the incidents happened in a geography class for first-year secondary school pupils.

About 39 children were in the class when the stream was hacked, before “two Caucasian men” appeared and made lewd comments. The class was stopped immediately.

“Home-based learning is supposed to be a safe space,” one parent told the Straits Times. “I know it’s difficult to manage but as a parent I feel very concerned.”

It’s not known how the hackers gained access. Zoom meetings have nine-digit IDs and can, in theory, be joined by any user if they are not protected by the organiser.