Zimbabwe has called for Walter Palmer, the US dentist who shot dead Cecil the lion, to be extradited to face poaching charges. Officials allege the 55-year-old Minnesota dentist broke the law by financing the shoot in which the lion, a much-loved tourist attraction, was killed after being lured from a nature reserve.

Environment minister Oppah Muchinguri said Zimbabwean authorities had already begun extradition proceedings against the "foreign poacher", who is believed to have paid up to £32,000 ($50,000) to take part in the hunt.

The Zimbabwean Embassy in Washington DC though said later that it had not yet received an extradition request to present to US authorities, NBC reported.

Palmer has not been seen in public since news broke that he killed Cecil on 1 July, initially shooting the animal with an arrow then finishing it off with a gun after tracking the wounded beast for miles.

A petition to the White House demanding that US authorities extradite Palmer to face justice reached 146,000 signatures on 31 July, surpassing the 100,000 mark required for the Obama administration to make a response.

Professional hunter Theo Bronkhorst and Honest Ndlovu, the owner of the land on which the lion was shot, appeared in court earlier in July charged with poaching. In a statement, Palmer said he regretted killing the lion, but was not aware of its identity. He said he believed he was on a legal hunt with professionals, who had obtained the necessary permits.