Zimbabwe has asked the United States to extradite Walter Palmer, the American dentist who killed a famous lion in Zimbabwe early this month, to face trial.

Environment Minister Oppah Muchinguri told a press conference in Harare that Zimbabwe's law enforcement agency has sent a request to its U.S. counterpart for Palmer's extradition.

"We are taking this issue very seriously. We want him (Palmer) to be extradited and tried in Zimbabwe," she said.

Palmer is said to have paid to hunt down the 13-year-old lion, known as Cecil, in Hwange national park on July 1, sparking a huge global backlash.

Two Zimbabweans, a professional hunter and a private farm owner, accused of involvement in Palmer's hunt, appeared in court Tuesday for illegal poaching. They were granted bail pending trial due in August.

Muchinguri said Palmer and the two Zimbabweans "deliberately" killed Cecil as they, though on trophy hunting, didn't get permission for hunting lion, and violated local hunting regulations by using a crossbow and arrows.

"It shows that the whole poaching event was properly orchestrated and well financed to make sure it succeeds," Muchinguri said.

Palmer earlier through his spokesman alleged that he followed his local guide in carrying out the hunt and didn't know it was illegal.

If convicted in Zimbabwe, Palmer could be jailed up to ten years over poaching.

An online petition to the White House, requesting Palmer's extradition, has gained more than 500,000 signatures with animal lovers protesting outside the dentist's office in Minnesota, blocking its entrance with stuffed animals.

Some conservationists also cast doubts over the allowance of trophy hunting in Zimbabwe.

"This case has opened up global attention on whether hunting is the right thing to do for conservation or not," said Charles Jonga, director of Community Areas Management Program for Indigenous Resources, a Zimbabwean wildlife conservation program.

Zimbabwe has around 2,000 lions in its game parks.

The country in 2011 lifted a seven-year hunting ban on lions. It now allows 50 to 70 lions to be killed by trophy hunters every year, according to Edson Chidziya, director general of the Zimbabwe Parks and Wildlife Management Authority.

The wildlife conservation authority is said to be cash-strapped as official figures show trophy hunting generates some 40 million U.S. dollars annually for Zimbabwe.

Part of the revenue is used in wildlife conservation and for aiding impoverished local communities whose cattle are said to be preyed on by wild animals from time to time.