A crash between a passenger bus and a van armored to carry cash in the northern province of Limpopo, South Africa, has killed at least 20 people and injured 68, officials have reported. The two vehicles collided head-on along the N1 freeway in the Makhado area on Monday evening, according to paramedics who responded to the crash.

The bus reportedly rolled down a slope to a river and some passengers were found trapped underneath.

Three people by the highway were confirmed dead while 16 other bodies were found by the river where the bus had rolled, according to ER24 Paramedics spokesman Ross Campbell.

"Most of the fatalities down the river had been trapped under the bus," said Campbell.

Ten of the injured were in serious condition, the regional transport department said.

Police divers were searching a river that runs along the highway "for people who might have been swept away," the department said.

One more person died after being taken to a hospital, Campbell said. Others injured received treatment at the site with some being transported to nearby health facilities for further care, he said.

While exact details surrounding the collision are unknown, heavy rains have been falling in the area, according to Campbell.

Downpours have caused flooding in several regions of South Africa in recent days, killing at least seven people and leading the government to declare a national disaster.

Police investigators were still on the scene on Tuesday morning, said Campbell.

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