Tragedy struck as four children and a young relative died in a house fire in Arizona, USA, while their father went to purchase Christmas gifts.

The fire tore through the two-storey home on Saturday evening, authorities said, leaving no survivors.

Four children, ages 2, 4, 5 and 13 were siblings, while an 11-year-old was a visiting relative.

Police officials are investigating the fire and have not released the names of the children or father.

The fire broke out in Bullhead City, 100 miles (160km) south of Las Vegas, just before 17:00 local time (1:00 GMT) on Saturday.

"The children's father reported to investigators that he was gone for approximately 2.5 hours to buy groceries and Christmas gifts," Bullhead City police said in a statement.

''The preliminary investigation found that the fire originated in the downstairs entranceway, "most likely making it impossible for the children in the upstairs bedroom to get out of the residence safely", authorities said.

All five victims were found in the same upstairs bedroom. Police say it seems the fire had made its way up the home's only staircase, blocking their escape.

Witnesses say as the fire tore through the house during the father's absence, frantic neighbours gathered hoses and ladders in an attempt to put out the fire.

"We pulled the garage door open, there was guys pulling stuff out," one witness, Patrick O'Neal, told local CBS News affiliate KTVK. "The closer we got to the door there was smoke starting to come into the garage and choking people out."

The neighbours were unaware that anyone was inside the home, he added. If they had known, he said they would have attempted a rescue.

Police say there were no adults home when the fire started.

On Wednesday night, December 20, a vigil will be held in a local park while a GoFundMe account has raised over $14,000 (£11,000) as of Tuesday to help the families cover funeral expenses.