A dentist who has become the target of worldwide outrage for hunting and killing a protected lion in Zimbabwe has advised his patients to seek care elsewhere as he remained in hiding amid protests at his US clinic.

Walter Palmer said he rarely discussed his big-game hunting because it can be a "divisive and emotionally charged topic".

Dr Palmer, 55, has faced protests at his clinic in Bloomington, a suburb of Minneapolis, Minnesota, where he offers general and cosmetic dentistry, as well as intense condemnation online. He has not appeared in public since being identified on Tuesday as a party to the lion's death.

He is an active big-game hunter, with many kills to his name, some of them registered with hunting clubs.

The North Dakota native "enjoys all outdoor activities", according to the biography page on his now-dark clinic website. "Anything allowing him to stay active and observe and photograph wildlife is where you will find Dr Palmer when he not in the office."

Meanwhile in Zimbabwe, a hunting guide and a farm owner appeared in court accused of herlping Dr Palmer kill the popular lion named Cecil.

The head of Zimbabwe's safari association said the big cat with the black mane was lured into the kill zone and denied "a chance of a fair chase".

The Zimbabwean men were accused of aiding Dr Palmer, who reportedly paid £32,000 to track and kill a lion. Zimbabwe police have said they are looking for Dr Palmer, whose exact whereabouts were unknown.

The dentist referenced the situation in a note to his patients. "I understand and respect that not everyone shares the same views on hunting," he said in the letter, obtained by the local Fox television affiliate KMSP.

The married father of two was the subject of a 2009 New York Times article about big-game hunting in which he said he learned to shoot at the age of five. The article said Dr Palmer had a reputation for being capable of "skewering a playing card from 100 yards" with a compound bow and having "a purist's reputation for his disinclination to carry firearms as back-up".

During the night-time hunt, the Zimbabwean men tied a dead animal to their car to draw the lion out of a national park, said Johnny Rodrigues, chairman of the Zimbabwe Conservation Task Force.

The American is believed to have shot the lion with a crossbow. The wounded cat was then tracked for 40 hours before Dr Palmer fatally shot him with a gun, Mr Rodrigues said.

A professional hunter, Theo Bronkhorst, was accused of failing to "prevent an unlawful hunt". Court documents said he was supervising while Dr Palmer shot the animal.

Bronkhorst was released on £640 bail after appearing in court in Hwange, about 435 miles west of the capital Harare. If convicted he faces up to 15 years in prison.

A second man, farm owner Honest Trymore Ndlovu, also appeared in court but was not charged and released from custody, his lawyer said.

The court documents made no mention of Dr Palmer as a suspect.

Using bait to lure the lion is deemed unethical by the Safari Operators Association of Zimbabwe, of which Bronkhorst is a member. The association has since revoked his licence.

"Ethics are certainly against baiting. Animals are supposed to be given a chance of a fair chase," Emmanuel Fundira, the association's president, said. "In fact, it was not a hunt at all. The animal was baited, and that is not how we do it. It is not allowed."

It was not entirely clear whether baiting is allowed by Zimbabwe law. Mr Fundira said the practice was both unethical and illegal. The conservation group Lion Aid says it is unethical but not expressly forbidden.

Dr Palmer attended dental school at the University of Minnesota and built his practice in the Minneapolis suburb of Bloomington. He said in a statement that he did not know the lion was protected and relied on his guides to ensure a legal hunt.

"I had no idea that the lion I took was a known, local favourite, was collared and part of a study until the end of the hunt," he said in statement issued through a public relations firm.

Cecil was being studied by an Oxford University research programme.

Social media was filled with condemnation of the killing just outside Zimbabwe's Hwange National Park. On Twitter, the hashtag cecilthelion was in wide use.

A couple of hundred protesters gathered on Wednesday outside Dr Palmer's office with signs, including one that said: "Let the hunter be hunted!" Signs were also taped on his office door.

Sarah Madison brought her two children, including her three-year-old son dressed in a lion costume. She said says the hunt, even if legal, was immoral and disgraceful.

Organisations that foster and defend big-game hunting distanced themselves from Dr Palmer, including those where he was a member.

Dr Palmer appeared in past versions of Safari Club International records dated as recently as July 5, but his name had been dropped from the standings as of Tuesday evening. Corresponding pages featuring photos of him with an African lion, a southern white rhinoceros and an African elephant remained accessible on the club's website.

Chip Burkhalter, the club's director of government relations, initially said he would respond to calls following a meeting, but then could not be reached.

Glenn Hisey, director of records for the Minnesota-based Pope and Young Club, where Dr Palmer registered some of his killings by bow, had said the group was concerned about the news from Africa.

"If he violated controlling game laws there, he might have violated controlling game laws other places," Mr Hisey said, adding that Dr Palmer's listings with the club could be examined as more facts emerged.

By Wednesday, Mr Hisey was declining to comment.

According to US court records, Dr Palmer pleaded guilty in 2008 to making false statements to the US Fish and Wildlife Service about a black bear he fatally shot in western Wisconsin.

He had a permit to hunt but shot the animal outside the authorised zone in 2006, then tried to pass it off as being killed elsewhere, according to court documents. He was given a year's probation and fined nearly £1,925.

Cecil is believed to have been killed on July 1 and his carcass discovered days later.