The U.S. Border Patrol said Wednesday that it found the wreckage of a small plane that disappeared two days earlier while carrying top U.S. and Mexico officials on a mission to survey flooding along the Rio Grande. There were no survivors.

The International Boundary and Water Commission said all four aboard the plane died, including the heads of its U.S. and Mexico sections.

The Border Patrol said it located the wreckage shortly after noon Wednesday in a rugged section of the Sierra Madre Mountains in Mexico, about 20 miles northwest of Presidio.

The dead included the leaders of the U.S. and Mexican sections of the IBWC, Carlos Marin of El Paso and Arturo Herrera, of Ciudad Juarez, Mexico. Also on board was Jake Brisbin Jr., executive director of the Rio Grande Council of Government. The chartered Cessna 421 was piloted by Matthew Peter Juneau, the IBWC said in a written statement.

The plane was reported missing after it did not land on time Monday in Presidio, a border town about 250 miles southeast of El Paso.

IBWC officials said the commissioners were headed to the area to inspect the ongoing flooding conditions in Presidio and Ojinaga, a Mexican city across the Rio Grande from Presidio. The flight plan included a detour into Mexico so the men could get an aerial view of the Luis Leon Reservoir where weeks of rain has prompted Mexican officials to release thousands of gallons of water into the Rio Conchos. That river flows into the Rio Grande.

Bill Brooks, a Border Patrol spokesman in Marfa, said Border Patrol agents and Customs and Border Protection air and marine officers identified the plane by its tail number.

The area is extremely rugged and Brooks said the crash site is only accessible by foot.