Mexico says one of its citizens died after a boat carrying Mexican migrants capsized in U.S. waters off Southern California.

The Foreign Relations Department said the boat collided with a U.S. Customs and Border Protection vessel early Thursday near Encinitas, California.

A statement said one woman died, one was seriously injured and two others suffered less severe injuries. It said 16 people were pulled from the water, apparently including the casualties.

The statement added that the boat was believed to be carrying "at least 20 people" and said the U.S. Coast Guard was searching for any others who might have been aboard the boat.

Mexico asked for an investigation of the incident.

Immigrant smugglers have been known to use open boats to sneak people from Mexico to the California coast.