A truck slammed into a bus carrying tourists to an Ecuadorean coastal town, killing five young British women and injuring 15 other people, officials said Sunday.

The victims, in their teens and twenties, were participating in a four-month language and volunteer program that was to take them through the Andes Mountains, according to Mark Davison, director of VentureCo Worldwide Ltd., the tour company that organized the trip.

The crash took place on Saturday evening when a truck carrying a load of sand smashed into the left side of the bus near the town of Jipijapa, between Quito and the coastal town of Puerto Lopez, Ecuadorean police said. The truck driver fled the scene.

The injured include 12 British tourists, an Ecuadorean tour guide and driver, and a French citizen, police officer Edison Chiluisa said.

Britain's Foreign Office identified the dead as Sarah Howard, 26, Rebecca Logie, 19, Elizabeth Pincock, 19, and Emily Sadler, 19, Indira Swann, 18. Their bodies were transported to the nearby port city of Manta, police said.

British Prime Minister Gordon Brown said he was "deeply saddened" by the news of the deaths.

Britain's acting ambassador traveled to Manta to ensure that the other injured travelers — whose conditions were not life-threatening — are "receiving proper medical care," the Foreign Office said in a statement.

"We will also help facilitate their return travel to the UK in due course," the statement said.

The lowland area in Ecuador's Manabi province where the crash took place is a popular ecotourism destination, famed for its pristine beaches and abundant flora and fauna.