Afghanistan, Jan. 3 -- Four people were killed when a helicopter crashed in mountainous terrain in Arizona, authorities said, prompting a federal investigation into the cause.

Four people were killed when a helicopter crashed on Friday, January 2, in mountainous terrain in the US state of Arizona, local officials said.

The crash occurred near Telegraph Canyon, about 103 kilometres east of Phoenix, at around 11 a.m., the Pinal County Sheriff's Office said in a statement posted on social media platform X.

All four occupants were killed, including the 59-year-old pilot and three young women aged 21, 21 and 22, according to the sheriff's office. Authorities said there were no survivors.

"Our prayers are with the victims and their families,"...