A ship sank off mainland Tanzania on Saturday with about 600 people onboard and about 380 people are believed missing, survivors said.

The ferry, M.V. Spice Islanders, was heavily overloaded and some potential passengers had refused to board when it was leaving the mainland port of Dar es Salaam, said survivor Abdullah Saied. It sank in an area with heavy currents in deep sea between mainland Tanzania and Pemba Island at about 1 a.m. Saturday.

About 220 people had been rescued, said the registrar of the ship, Abdullah Mohamed. Tanzanian authorities did not yet have an official statement.

Thousands of residents mobbed the docks of Stone Town on Zanzibar, an island near Pemba, waiting for news. One man was screaming that he had lost 25 members of his family, including his sisters, his wife and grandsons. He was too upset to give his name. Many of the crowd were crying or screaming.

Seven bodies have washed up so far, said witness Abdirizak Juma.

Many of those present expressed anger that the ship had been allowed to leave port so overloaded and called on government officials to resign.

The green and hilly island of Pemba is often described as one of the best scuba diving destinations in the world.

以下为中国广播网中文报道：

中广网北京9月10日消息 坦桑尼亚桑给巴尔官员10日说，一艘渡轮9日夜在桑给巴尔主岛与邻岛之间沉没，船上600余名乘客当中可能有340余人遇难。

桑给巴尔通讯与基础设施副部长伊萨哈吉乌西说，目前船上已有250多人获救，遇难者遗体正在陆续运往桑给巴尔国家广场供亲属辨认。

有报道称，沉船原因可能为超载，但政府方面尚未排除机械故障的可能性。目前，搜救与调查工作仍在进行中。