Johannesburg, South Africa — America pressed China yesterday to halt a shipment of weapons to Zimbabwe and stop further sales amid mounting international pressure against the deliveries.

State Department spokesman Tom Casey said America had asked Beijing “to refrain from making additional shipments and, if possible, to bring this one back,” referring to the cargo of the An Yue Jiang.

The Chinese foreign ministry had said earlier that the An Yue Jiang “may return to China” if it was not allowed to unload its cargo, but insisted the vessel was “engaged in perfectly normal trade.”

Dubbed “the ship of shame” in South Africa, the An Yue Jiang is believed to be carrying three million rounds of ammunition, 1,500 rocket-propelled grenades and 2,500 mortar rounds.

While they were ordered last year, the opposition Movement for Democratic Change said it feared that the weapons could be used to “wage war” on its supporters prior to a possible run-off in Zimbabwe’s presidential vote involving President Mugabe and Morgan Tsvangirai. Mr. Casey said: “We don’t think that under the present circumstances, given the current political crisis in Zimbabwe, that now is the time for anyone to be increasing the number of weapons and armaments available in that country.”

America said it would press African nations to refuse the An Yue Jiang docking rights or face worsened relations with Washington.