A 50-year-old teacher who sparked a nationwide "amber alert" in the US when he vanished with a 15-year-old schoolgirl has been arrested and the girl found safe and well.

Tad Cummins, from Tennessee, and Elizabeth Thomas were found in California, the Tennessee Bureau of Investigation (TBI) announced in a tweet on Thursday (20 April).

The TBI said Cummins and Thomas had been found at a commune near the Shasta-Trinity National Forest, 120 miles (190km) south of the Oregon border.

Cummins is now in custody awaiting extradition back to Tennessee. He will face charges including sexual contact with a minor and aggravated kidnapping.

Cummins is believed to have evaded capture by changing his identity and possibly switching plates on his Silver Nissan Rogue, Fox News reported.

The TBI said he was believed to be armed with two handguns. He had been sacked from his job amid reports of an inappropriate relationship with the schoolgirl he taught at Culleoka Unit School, Maury County. Thousands of people contacted amber alert with tips and possible sightings.

"Our intelligence analysts and agents have worked tirelessly since issuing this AMBER Alert to process more than 1,500 leads from all 50 states," said TBI Director Mark Gwyn in a statement. "What happened in California this morning, however, proves it only takes one person to lead to a successful end. We are extremely thankful the hard work of all partners in this search has paid off. We're also grateful for the public's support and vigilance throughout this search effort."

So-called AMBER alerts - short for "America's Missing: Broadcast Emergency Response" are used across the US and many other countries to widely publicise cases where children go missing. According to its website, "As of December 2016, a total of 857 children had been successfully recovered through the AMBER Alert system."