CIUDAD JUAREZ, Mexico — A small plane carrying the U.S. and Mexican heads of the International Boundary and Water Commission crashed near the border, killing all four on board, a Mexican governor said Tuesday.

Chihuahua state Gov. Jose Reyez Baeza said the Cessna 421 was found early Tuesday near the town of Ojinaga, across from Presidio, Texas.

He said U.S. commissioner Carlos Marin; his Mexican counterpart, Arturo Herrera; Jake Brisbin Jr., executive director of the Rio Grande Council of Governments; and the pilot all died.

Reyes Baeza said U.S. investigators located the crash site.

Officials started looking for the aircraft Monday after it failed to land as scheduled in Presidio, about 250 miles southeast of El Paso.

Sally Spener, a spokeswoman for the IBWC, said the plane left El Paso just after 10 a.m. Monday and was scheduled to fly over the Luis Leon Reservoir in northern Mexico. The officials were there to get an aerial view of floodwaters that are threatening levees on both sides of the border and that have prompted the evacuation of hundreds of people.

Marin had worked with the IBWC's U.S. section since 1997. He was named interim commissioner in 2005 and took the title permanently a year later on an appointment from President Bush.

Herrera had led the Mexican section of the IBWC since 1989.

The international agency is responsible for maintaining the border between the U.S. and Mexico. In areas divided by the Rio Grande, that includes building and maintaining levees.

Spener said Tuesday that a levee along the Rio Conchos, a river that feeds into the Rio Grande, failed Monday night. Floodwaters were reported in low-lying areas on the western side of Ojinaga. Monday afternoon, houses and businesses near the Rio Grande levee in the Mexican border city were lined with sandbags and appeared empty.

"We understand it (the levee break) is affecting low lying areas in Ojinaga," Spener said. "That did relieve some of the flows that have been in the Rio Grande but we do expect that water levels will rise."