SAN SALVADOR – Fifteen vehicles, including six buses, collided on a highway in northwestern El Salvador, leaving at least 53 injured and an enormous traffic jam that blocked the road for close to six hours, emergency officials said.

The multiple accident occurred Monday on the highway between the city of Santa Ana and San Salvador near the village of El Congo, located 50 kilometers (31 miles) northwest of the capital, an emergency services spokesman told Efe.

In the driving rain, two buses belonging to an assembly plant plunged down a shallow ravine while the other vehicles remained jammed up on the road after having to brake suddenly, police and rescue workers said.

Speeding was a probable cause of the accident, police spokesmen said.

Emergency services workers and police who responded to the accident helped rescue dozens of passengers and drivers who were trapped in the pile-up.

Fifty-three people, including one in serious condition, were treated at the hospital in Santa Ana, the Salvadoran Social Security Institute’s public affairs office told Efe.

One of the bus drivers was speeding, but the suspect attributed the accident to a mechanical failure that supposedly made the vehicle keep accelerating until it crashed into the ravine, the National Civilian Police said.

The highway remained closed from 6:30 a.m. until noon on Monday. EFE