A ferry carrying more than 250 people has capsized between the east African coast and the Zanzibar archipelago, killing at least 31 people.
Police commissioner Mussa Ali Mussa said 145 people, including some foreign tourists, had been rescued but a number remain missing.
The ferry, MV Skagit/Kalama, set sail from mainland Tanzania heading for Zanzibar, Tanzania's semi-autonomous islands and a popular tourist destination.
"The latest count that we have is 31 people dead and 145 were rescued. We have suspended the rescue operation for the night, but we will resume it at first light in the morning," Mr Mussa said.
"The passenger boat had between 250 and 300 people on board when it capsized in rough seas."
Government spokesman Yusuf Chunda said a foreigner was among those killed, but it was not clear how many others had been on board the vessel.
"One foreigner, a woman, is among the dead. Thirteen other foreigners were rescued and are in hospital," Mr Chunda said.
Earlier, police said the vessel was carrying 250 adult passengers and 31 children when it capsized near Chumbe island, west of Zanzibar.
Zanzibar police spokesman Mohammed Mhina said many passengers were missing but added "we don't know how many of them sank with the boat".
"Almost the entire boat has been submerged in water ... only a small part of the boat is now visible."
More than 200 people were killed when a crowded ferry sank in September off the coast of east Africa in the worst maritime disaster in the history of Zanzibar.