Five children, including four siblings, were tragically killed in a house fire over the weekend as their guardian was out Christmas and grocery shopping. 

The fire started around 5 p.m. Saturday in a two-story duplex in Bullhead City near the Arizona-Nevada border, the Bullhead City Police Department said Monday. 

The children, a 13-year-old boy, a 5-year-old boy, a 4-year-old girl and a 2-year-old boy, were all siblings. An 11-year-old boy was a relative and visiting at the time.

Their names are being withheld pending official identification by the Mohave County Medical Examiner’s Office.

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Image of an Arizona house fire from the outside

A house fire at a two-story duplex in Bullhead City, Arizona took the lives of five children inside over the weekend, authorities said.  (Fox 10)

The fire originated in a downstairs foyer area, "most likely making it impossible for the children in the upstairs bedroom to get out of the residence safely," a police statement said. 

The fire then traveled up the staircase, which prevented the children from escaping, authorities said. 

The father of the siblings told authorities he left for two and a half hours to buy groceries and Christmas gifts. Several neighbors attempted to rescue the children, including placing an extension ladder to the upstairs bedroom, police said.

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"I mean, that’s five, innocent children that had nothing but the lives ahead of them. You don’t process that, it doesn’t make sense, you can’t put rationality to this situation, there’s no way you can tell yourself it’s going to be OK. It’s not OK," community member Shawn Jacobson told Fox Phoenix.

The Bullhead City Police Department, the Lake Havasu Fire Department and fire investigators with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) are working to determine the cause of the fire, said Bullhead City Police Chief Robert Trebes.

A flower memorial outside a burned home where five children were killed

A makeshift memorial located outside the Bullhead City, Arizona, home where five children were killed in a Saturday fire.  (Fox Phoenix)

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The children's grandfather was a firefighter with the Bullhead City Fire Department, so other agencies are helping to investigate in its place, Fox Phoenix reported. 

In a video statement, Trebes said the community was "suffering" over the loss of the children. 

"And the parents and loved ones of those who perished in this fire Saturday night are grieving," he said.