New York authorities are searching for 9-year-old Charlotte Sena who vanished while biking on a camping trip in a state park

The girl was last seen around 6:15 p.m. ET riding her bike in one of the park’s loops, Lt. Colonel Richard L. Mazzone, of the New York State Police, said in the news conference.

At about 6:45 p.m., her bike was found in the loop, Mazzone said.

Two minutes later, her mother called authorities to report her missing.

Charlotte was last seen wearing an orange tie-dyed Pokémon shirt, dark blue pants, black Crocs and a grey bike helmet, according to a description provided by the state police. She is White with blonde hair, about 4’ 6” tall, with green eyes, authorities said.

An AMBER alert was issued Sunday morning, Mazzone said.

“We took that step of issuing the AMBER alert because we felt, after (our) exhaustive search, when we couldn’t find her here, it was quite possible that an abduction had taken place,” he added.

For more than 18 hours, state authorities have been searching for the child and have deployed aviation and underwater rescue teams, blood hounds, drones and technology experts have also been called in to analyze “other forms of communications in the park at that time,” the governor said.