Several people in the Philippines were injured when an escalator at a sprawling mall that was taking them one floor up abruptly slid backwards, causing a terrifying pile-up.

The incident happened at around 5pm on Sunday in Santa Rosa city, an hour south of the capital Manila.

A video posted on YouTube shows the escalator carrying a large crowd of people up one floor when its steel steps appeared to lose their grip and abruptly began sliding backwards.

For the first two seconds, those on the escalator were able to hold on to the handrails.

But as their descent gathered speed, many of them lost their balance, and they were soon piling on top of each other at the foot of the escalator.

It took about seven seconds before the escalator’s fail-safe mechanism appeared to kick in and the escalator stopped.

“Everyone on the escalator fell down; some had blood on them,” GMA News Online quoted a witness as saying.

Ms Gretchen Manaig, 34, told the online entertainment site PEP that three of her children – ages five, six and 12 – were among those who were injured when people fell on top of them.

She said she, her husband and three children were at the foot of the escalator and were already heading up when the steps buckled and began sliding backwards.

Suddenly, up to 10 people were on top of them, she recalled.

“We didn’t know what happened. It all happened so fast,” Ms Manaig told PEP.

She said her children are now terrified to step on an escalator.

Officials at the SM Group, the mall’s operator that runs the Philippines’ largest retail chain, said they have reached out to those with injuries to help them with their medical bills.

“The area has been properly secured, and a thorough investigation into the matter is already ongoing,” they said in a statement.

GMA News reported that inspectors from the city government would also be checking the escalator to ascertain what exactly happened.