Fear are growing that Robert Mugabe's regime had been strengthened ahead of a presidential election with the secret delivery of a shipment of arms from China.

Reports said the weapons, including three million bullets, mortar bombs and rocket-propelled grenades, had been off-loaded from the Chinese vessel, the An Yue Jiang, at the Angolan port of Lobito and flown to Harare.

The ship had been the focus of international condemnation when it sailed towards South Africa last month. It was refused docking rights and remained off the coast for several weeks before the Chinese foreign ministry recalled it.

However, Bright Matonga, Zimbabwe's deputy information minister, was quoted by the South African newspaper, The Weekender, as saying that the regime has the weapons.

Two Zimbabwean ministers and senior army officers visited Luanda three weeks ago to negotiate the docking and unloading of the ship.

George Chiramba, a spokesman for Mr Mugabe, said in the state-controlled newspaper, The Herald, that "the arms will be delivered to Zimbabwe, one way or the other".

The Chinese foreign ministry said yesterday that confirmation of the delivery was "groundless rumour".

The reports came days after the election commission in Zimbabwe announced the delayed presidential run-off would take place on June 27.

The opposition Movement for Democratic Change, whose leader Morgan Tsvangirai delayed his return to Zimbabwe at the weekend due to "credible" reports of an assassination attempt, said it feared the shipment would be used to intimidate civilians "whose only crime is rejecting dictatorship and voting for change".

Mr Tsvangirai maintains he won the first round of the presidential election by more than the required 50 per cent to avoid a run-off. Official results state that while he had beaten Mr Mugabe, he did not gain an outright victory.

James McGee, the US ambassador to Zimbabwe, has warned that violence is making a fair second round run-off vote impossible. He claimed he had evidence that the police and military had been involved in "pure, unadulterated violence designed to intimidate people from voting".