GUATEMALA CITY (AFP) - Two adults were dead and two children injured when an amusement park ride derailed in Guatemala over the weekend, officials said on Monday.

The accident, on a ride called the "Russian Mountain," occurred in the town of Quetzaltenango, some 200km west of Guatemala City, officials said.

"We still don't know what caused one of the cars, which was carrying four people, to leave the rails," said fire department spokesman Alvaro Perez.

"Unfortunately, an 18-year old woman and a 25-year old man lost thier lives" after suffering "blows to the head" during the accident.

The children, aged 11 and 12, were in "delicate" condition after suffering broken bones and other injuries and were being treated at an area hospital, Mr Perez said.