Zimbabweans have failed in their responsibility to protect a popular lion named Cecil that was killed by an American in an allegedly illegal hunt, president Robert Mugabe has said.

In his first public comments about the lion, Mr Mugabe said Zimbabweans should protect their natural resources from what he called foreign "vandals".

"All the natural resources are yours. Even Cecil the lion is yours. He is dead but yours to protect, and you failed to protect him," Mr Mugabe said in a televised speech marking Heroes' Day, a national holiday honouring fighters who died in the war to end white minority rule.

"There are vandals who come from all over. Some maybe just ordinary visitors, but there are others who want to vandalise, to irregularly and illegally acquire part of those resources," Mr Mugabe said.

"All this wildlife is yours, we should protect them," he said. "They should not be shot by a gun, it's a sin. Or an arrow. I was stopped from killing animals with an arrow when I was seven or eight years old. I was told: 'These are God's creatures.'"

Zimbabwe has a legal hunting industry, though wildlife officials said James Walter Palmer, the American who killed Cecil, did not have authorisation for the hunt.

A Zimbabwean cabinet minister has called for the extradition of Dr Palmer, who says he relied on his professional guides to ensure the hunt was legal.

Two Zimbabweans - a professional hunter and a farm owner - have been charged over Cecil's killing.

Zimbabwe has also banned the hunting of collared animals and said those involved in illegal hunts would be banned from hunting for life. Cecil the lion was wearing a satellite collar installed by a team of wildlife researchers.

Wildlife authorities also lifted a temporary ban on hunting of some species in areas around Hwange National Park, which had been Cecil's habitat.

"All lion, leopard and elephant hunts should be accompanied by parks staff whose costs will be met by the landowner," officials said.