Officials say they are fighting a 13-mile-long (21-kilometer-long) fuel-oil spill caused by the collision of two ships just outside the harbor of Uruguay’s capital.

Navy Capt. Marcelo Larrobla says an undetermined amount of fuel oil was released after the Greece-registered Syros slammed against the Malta-registered Sea Bird near Montevideo on Wednesday.

Authorities are trying to control the spill with floating barriers. No one on either ship was injured but the Syros was damaged near the fuel tank, which apparently produced the spill.

Larrobla says the collision was likely caused by a wrong maneuver by the Syros, although it is still being investigated. He says a southeast wind will likely prevent the oil slick from reaching Uruguay’s coast.