Emergency workers in South Africa are searching for the bodies of victims after a bus carrying pilgrims to an Easter gathering plunged off a bridge and caught fire.

An eight-year-old child was the only survivor of the crash that killed at least 45 people.

Hours after the Thursday afternoon crash, smoke seeped from the mangled wreck underneath the concrete bridge.

Authorities said it appeared that the driver lost control and the bus ploughed into the barriers along the side of the bridge and then over the edge. The driver was among the dead.

The crash happened in a mountainous region near the town of Mokopane, which is about 125 miles north of the South African capital, Pretoria.

The Limpopo provincial government said the bus, which was carrying pilgrims from Botswana, veered off the Mmamatlakala bridge and plunged 50 metres into a ravine.

“We were at the scene,” said local resident Simone Mayema, who said he was one of the first to arrive. “We tried to help (but) there was nothing we could do because there was flames.”

Forensic investigators worked through the wreckage early on Friday, but while some bodies had been recovered, others were believed to be still inside what was left of the bus, which was almost crushed flat.

There was no new information on the status of the child who somehow survived the horrific crash. Officials at the hospital where the child was taken declined to give an update. Government officials were expected to hold a press conference later on Friday.

South African President Cyril Ramaphosa said the victims appeared to be all from Botswana and had been on their way to the town of Moria in Limpopo for a popular Easter weekend pilgrimage that attracts hundreds of thousands of worshippers from South Africa and neighbouring countries who follow the Zion Christian Church.

Mr Ramaphosa had phoned Botswana President Mokgweetsi Masisi to offer his condolences and said the South African government would do all it can to help, according to a statement from Mr Ramaphosa’s office.

Provincial authorities said the bus had a Botswana number plate.

South African Minister of Transport Sindisiwe Chikunga was in Limpopo province for a road safety campaign and changed her plans in order to visit the crash scene on Thursday after hearing the “devastating news”, the national Department of Transport said.

Ms Chikunga said there was an investigation under way into the cause of the crash and offered her condolences to the families of the victims.

The South African government often warns motorists to be cautious during the Easter holidays, which is a particularly busy and dangerous time for road travel as millions of South Africans travel from cities back to their rural family homes or make religious trips.

Foreigners also make long road journeys back to their neighbouring home countries as Easter Friday and Easter Monday are both national holidays, giving people four days off.

More than 200 people died in road crashes during the Easter weekend last year. Just a day before this crash, the South African government called on people to be extra careful on Thursday and Friday because of the expected high volumes travelling by road, including around Moria.