Thirteen people were killed in a bloody shootout in Mexico between drug gang members and Mexican marines on an island off the Texas border, authorities said.
Twelve suspected members of the Zetas drug gang and one marine died in the gunfight on Sunday, which took place in Falcon Lake in the narco war-torn state of Tamaulipas.
The lake was the site of a mysterious tourist shooting last year.
Mexican Navy officials said the skirmish started when marines on patrol in the lake discovered a suspicious-looking campsite on the island and drug thugs opened fire to protect their turf.
Officials said the gang was using the island as a jumping off point to smuggle marijuana into the U.S. using speedboats.
Marines found a cache of assault rifles and other weapons hidden there, the Navy said.
Falcon Lake, a section of the Rio Grande about 40 miles south of Laredo, Texas, made headlines last fall after a woman said Mexican pirates chased down and shot her husband in the head. The pair had been riding jet skis back from the Mexican side of the lake.
Mexican officials called off a search for David Hartley on Oct. 14, shortly after the lead investigator on the case, Police Commander Rolando Flores, was killed and decapitated.
Hartley's body has not been found.
In March, authorities in Zapata County, Tex., said they had identified four suspects in the killing and that all of them were Zetas.
The sheriff's office said it has warned boaters about the dangers of drifting into the Mexican side of the lake.
President Obama made his first trip as president to the border on Tuesday, visiting El Paso, about 700 miles west.
The trip kicks off a series of speeches the President has planned to court Latino voters and talk about immigration reform.