People can now help track missing children in their area in the US by simply logging onto their Facebook account.

The social network has teamed up with the National Center for Missing and Exploited Children (NCMEC) to send Amber Alerts including photographs and other details to users in specific areas where the child has disappeared.

"The chances of finding a missing child increase when more people are on the lookout, especially in the critical first hours," Emily Vacher, trust and safety manager at Facebook, said in a statement. "Our goal is to help get these alerts out quickly to the people who are in the best position to help."

When police issue an Amber Alert prompted by the NCMEC it will be automatically sent to Facebook users via their phone or computer.

"It may include a picture of the child, a vehicle description, any information that the public would need to be able to help find the child," Vacher said.

More than 725 children have been recovered as a direct result of Amber Alerts since the voluntary program was launched in 1996. It was set up following the kidnapping and murder of nine-year-old Amber Hagerman in Arlington, Texas.

"We know the system works. We hope our new delivery mechanism will help increase that number and reunite even more families," she added.

US Attorney General Eric Holder, following Tuesday's announcement, said: "The more vigilant the citizens we have on the lookout, the better our chances of a quick recovery."