JOHANNESBURG (Reuters) - A bus carrying British tourists crashed on a notorious mountain road in northeast South Africa on Thursday, killing two 19-year-old women and injuring 21 on the eve of the continent's first World Cup, police said.

The tourists did not appear to be in South Africa for the soccer tournament since they had tickets to leave by air on Friday, provincial police spokesman Leonard Shlati said.

"The bus overturned on a windy road at a bend," he told Reuters. "There's one critical in hospital. The rest should be OK."

One critically injured passenger was rushed by ambulance to hospital in Nelspruit, a World Cup host city 400 km (250 miles) east of Johannesburg. The accident occurred at about 0830 GMT, near the town of Barberton, police said.

South Africa's roads, especially in the mountainous areas along its northeastern borders with Mozambique and Swaziland, are notorious for accidents.

World Cup organizers identified transport as one of the tournament's major challenges.

(Reporting by Diana Neille and Xhola Potelwa, writing by Ed Cropley; Editing by Michael Holden)