JOHANNESBURG, South Africa (AP) — A Chinese ship carrying weapons destined for Zimbabwe's government left the South African harbor where workers refused to unload it Friday and headed for neighboring Mozambique, an independent human rights group said.

The ship sailed from Durban on Friday evening soon after a high court ordered that the cargo not be moved, said Nicole Fritz, director of the Southern Africa Litigation Center, which asked the court to intervene to stop the arms from being transported to politically troubled Zimbabwe.

The ship An Yue Jiang had anchored just outside Durban harbor after receiving permission late Wednesday to dock. Its arrival earlier this week increased concern about tensions in Zimbabwe, where the ruling party and the opposition are locked in a dispute over who won the presidential election.

A South African government official, speaking on condition of anonymity because of the sensitivity of the issue, had confirmed weapons were on board but gave no further details.

Fritz said the Durban High Court granted an order suspending the ship's conveyance permit and saying there should be "no movement of the containers in which the arms are kept and no movement of the ship."

However, she said, lawyers were told by the court's sheriff that when an attempt was made to serve the order on the ship, the vessel was already sailing away, she said. She said other sources had confirmed the ship was headed for Mozambique, which lies on landlocked Zimbabwe's eastern border.

Port workers in Durban and truck drivers had said earlier in the day that they would not unload the weapons or transport them to Zimbabwe.

The umbrella Congress of South African Trade Unions applauded the stance by the South African Transport and Allied Workers Union, and reiterated its calls for Zimbabwean electoral officials to release the results of the March 29 presidential election.

"This vessel must return to China with the arms on board, as South Africa cannot be seen to be facilitating the flow of weapons into Zimbabwe at a time where there is a political dispute and a volatile situation," the union congress said in a statement.

China is one of Zimbabwe's main trade partners and allies.

The union move added to pressure on President Thabo Mbeki to take a harder line on Zimbabwe. Mbeki has argued that Zimbabwean President Robert Mugabe, who is accused of withholding election results, is unlikely to respond to a confrontational approach.

Cardinal Wilfrid Napier, the archbishop of Durban and spokesman of the Southern African Catholic Bishops' Conference, called Friday on Mbeki's government "not to allow any more arms and munitions to enter Zimbabwe through South Africa until an acceptable solution is found to the present situation."

Mary Robinson, the former U.N. human rights chief, applauded the unions for taking a stand.

"How positive it is that ordinary dockers have refused to allow that boat to go further," Robinson said during a conference in Senegal on governance in Africa. "They as individuals have taken the responsibility. Because they believe it's not right."