Uganda's government has suspended all school trips in the wake of Thursday evening's bus crash that killed at least 20 pupils and one adult who were taking part in an educational tour.

Dozens of others, including staff, were injured in the accident in Kapchorwa district, eastern Uganda.

Preliminary investigations suggest the bus had a mechanical fault before the driver lost control on Chekwatit Hill, a stretch of road that has been the site of several serious crashes, according to local officials.

Uganda records thousands of road deaths a year but this incident is one of the country's deadliest involving children in recent times. 

"As an immediate precautionary measure, we must do something about the safety of our children," Education Minister John Chrysostom Muyingo said, announcing the temporary ban on trips until a full investigation was completed.

"The nation has suffered a great loss, I would like us to work hand in hand so that those who survived are well taken care of," he added.

Traffic police spokesman Michael Kananura described what had happened on Thursday. 

"The driver reportedly lost control of the vehicle, which veered off the road, struck a large stone along the roadside, and overturned," he said.

The bus, carrying pupils from King David Junior School in Ndejje, crashed at about 20:00 local time (17:00 GMT) at Chekwatit village.

"Sadly, 20 children and one adult, who happens to be the founder and director, Mr Tadeo Ssekade, have gone to be with the Lord," Local Government Minister Balaam Ateenyi Barugahara posted on X, while he was at the scene. 

Videos shared by eyewitnesses showed the bus badly damaged, as local residents rushed to help the injured children.

The pupils were returning from a study tour, with local media reporting they had visited the Sipi Falls, a tourist area. 

Speeding, poorly maintained vehicles and dangerous roads are among the leading causes of road deaths in Uganda, according to traffic authorities. 

The latest crash comes amid renewed concern over the safety of school transport after several serious bus accidents were reported in the country in recent weeks.