Amidst growing outrage across the world over the killing of Cecil the lion, Zimbabwe has called on the U.S. to extradite Walter Palmer, the American dentist who shot the prized tourist draw earlier this month.

In Harare's first official comments since the death of Cecil, described as the black-maned lion who was well-known to foreign tourists in the Hwange National Park - as an "iconic attraction," Zimbabwe environment minister, and a senior member of President Robert Mugabe's ruling ZANU-PF party, Oppah Muchinguri said the Prosecutor General had already started the process to have 55-year-old Palmer extradited from the U.S.

"The illegal killing was deliberate. We are appealing to the responsible authorities for his extradition to Zimbabwe so that he can be held accountable for his illegal actions," Muchinguri said at news conference, Reuters reported.

According to Muchinguri, the government wanted him tried in Zimbabwe "because he violated our laws. Police should take the first step to approach the prosecutor general who will approach the Americans. The processes have already started. Unfortunately it was too late to apprehend the foreign poacher as he had already absconded to his country of origin. We are appealing to the responsible authorities for his extradition to Zimbabwe so that he be made accountable," Irish Examiner reported.

Meanwhile, as social media across the world has exploded in outrage against Palmer, the White House said on Thursday that it would review a public petition of more than 100,000 signatures to have him extradited. The petition needed to receive 100,000 signatures by Aug. 27 to get a response, and it had more than 160,000 signatures by Friday, according to CNN.

Amid the international uproar, Palmer's whereabouts remain unknown.

The U.S., for its part, has started investigations into the incident. "Investigation will take us wherever the facts lead. At this point in time, however, multiple efforts to contact Dr. Walter Palmer have been unsuccessful. We ask that Dr. Palmer or his representative contact us immediately," said Edward Grace, the deputy chief of law enforcement at The U.S. Fish and Wildlife Service, which is also investigating the circumstances of the lion's death, CNN reported.

In Zimbabwe, the illegal killing of a lion is punishable by a mandatory fine of $20,000 and up to 10 years in prison.