China said a shipment of arms bound for Zimbabwe would be recalled after South African workers refused to unload the vessel and other neighbouring countries barred it from their ports.

The top U.S. diplomat for Africa, Jendayi Frazer, on a tour of Zimbabwe's most influential neighbours, stood behind the British proposal for an embargo to put pressure on President Robert Mugabe over Zimbabwe's election crisis.

"We think the idea of Prime Minister Gordon Brown for an arms embargo is a good one," Frazer told reporters in Pretoria.

"It will send a great warning to those who would send arms into Zimbabwe, including the Chinese."

The recall of the Chinese An Yue Jiang, carrying 77 tonnes of assault rifle ammunition, mortars and rifle grenades, came after unprecedented regional opposition in addition to Western pressure over the election.

No results have been announced for the March 29 presidential vote, while the outcome of a parliamentary poll which the opposition won is also in doubt because of partial recounts.

Movement for Democratic Change leader Morgan Tsvangirai has said he won the presidential election outright and has accused Mugabe of delaying results to rig victory and keep his 28-year hold on power.