Image copyright Getty Images Image caption The interior of the auger is shaped like a screw and twists to pull up grain

A Nebraska farmer has sawed off his own leg with a pen knife after becoming trapped in farming equipment.

Kurt Kaser, 63, was moving grain from one silo to another when he was pulled into an auger - a tube with an interior shaped like a screw.

He was forced to cut off his lower leg with a 3in (7.6cm) pen knife and crawl to the nearest phone for help.

The farmer spent weeks in hospital and rehabilitation before returning home to Pender near the Iowa border on Friday.

"I didn't have no other choice," Mr Kaser told broadcaster ABC News .

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The farmer was working alone on his 1,500-acre (607-hectare) property on 19 April when the accident occurred.

Unable to find his phone to call for help, Mr Kaser watched as the machine tore his foot off and mangled his lower leg as it pulled him further inside.

The farmer then took out his pen knife and cut off what remained of his limb below the knee.

"The bone stuck out down to my ankle," told Omaha World-Herald . "That's what I was hanging onto as I was trying to get myself out."

Once free, Mr Kaser crawled hundreds of feet to the nearest phone and called his son, who picked him up and drove him into town. He was then flown to the state capital Lincoln for treatment.

Mr Kaser said he had removed a safety covering at the end of the auger in the winter to make the equipment fit under a grain bin, and told ABC News he was "kind of disappointed in myself that I didn't think of fixing that thing".

"But that's why they call it accidents I guess."