A US dentist who killed Cecil the lion during a hunt at Hwange National Park in Zimbabwe has returned to work at his practice.

Walter Palmer, who faced a global backlash after it emerged the lion had been killed in July, entered his office in suburban Minneapolis on Tuesday morning without commenting to waiting journalists.

A member of staff from the clinic met him on the pavement, grabbed his arm and walked him through members of the media to the front door.

Employees have also been escorting patients from their vehicles into the building.

A small group of protesters gathered outside the clinic, with some shouting "extradite Palmer" as he walked past.

On Sunday, Mr Palmer (55) insisted he acted legally and that he did not know Cecil was one of Zimbabwe's most treasured animals in an interview with the Associated Press and the Minneapolis Star Tribune.

He said: "If I had known this lion had a name and was important to the country or a study obviously I wouldn't have taken it".

"Nobody in our hunting party knew before or after the name of this lion".

Mr Palmer's practice was temporarily closed as controversy over Cecil's killing raged. It reopened in late August without Mr Palmer, who described himself as "heartbroken" for causing disruption to his staff.

The dentist said he shot the big cat, which was fitted with a GPS collar as part of Oxford University research, using an arrow from his compound bow outside the park's borders.

He said Cecil, a rare black-maned lion, did not die immediately and was tracked down the next day before being killed with another arrow.

A lawyer for Mr Palmer told Associated Press news agency that he had offered to make his client available to the US Fish and Wildlife Service to talk about the case weeks ago, but they had not heard back.

After he was named as the hunter who had killed Cecil, protests erupted outside the clinic in Bloomington and his home in Eden Prairie, and a holiday property in Florida was vandalised.