A magnitude 5.7 earthquake has killed at least 11 people and injured 192 in northern Tanzania, the authorities say.
The quake struck close to the border with Uganda and Rwanda near Lake Victoria.
Images posted on social media showed significant damage to buildings in Bukoba, a city of more than 70,000 people where most casualties were reported.
Tremors were felt as far away as western Kenya.
"This incident has caused a lot of damage," Deodatus Kinawila, the district commissioner of Bukoba, told the BBC.
"As we speak now, the number of injuries stands at 192 and 11 dead. Because we are still collecting the information it's likely to go up. Even the number of injuries is likely to go up."
Rescue workers have told the BBC that local hospitals are full and cannot cope with the number of injured. Buildings have collapsed and people are still trapped underneath the rubble.
The US Geological Survey says the quake struck at a depth of 10km (six miles) at 15:27 local time (12:27 GMT).
East Africa's Great Rift Valley runs along a geological fault line but major earthquakes there are rare.
A magnitude six quake struck the Tanzanian town of Arusha, east of Bukoba, in July 2007.