Authorities in Texas recovered four bodies, including an infant girl, from a river along the U.S.-Mexico border over just 48 hours , officials said Monday.

Lt. Chris Olivarez, a spokesperson with the Texas Department of Public Safety, said two of the bodies were pulled from the Rio Grande on Saturday, one on Sunday and another on Monday.

"The identities of the deceased remain unknown since none possessed identifying documents," Olivarez tweeted Monday.

On Saturday, authorities responding to a request from U.S. Border Patrol "regarding a possible infant drowning" found four people floating in the river, including an unresponsive woman and baby girl, Olivarez said. Lifesaving measures were performed but both were later pronounced dead at Fort Duncan Regional Medical Center in Eagle Pass, Texas.

The two others pulled from the river survived and were turned over to U.S. Border Patrol, the spokesman said.

Authorities also recovered the body of an unidentified male from the river on Sunday and then the body of an unidentified female on Monday, Olivarez said.

Crossing the river, which spans nearly 2,000 miles and divides Texas and Mexico, is a common but perilous route for migrants attempting to make it unlawfully north of the border. Last September, nine migrants trying to enter the U.S. were found dead in the Rio Grande.

Also on Monday, Texas Department of Public Safety troopers found two young children from Guatemala left abandoned at the edge of the Rio Grande in Eagle Pass, Olivarez said. The children, ages 8 and 11, told troopers a woman left them at the edge of the river on the Mexican side and told them to cross it.

"Children who are smuggled/trafficked across the Texas-Mexico border continue to be exploited & left abandoned in dangerous situations," Olivarez tweeted, adding that more than 900 children had been recovered by the Department of Public Safety in smuggling and trafficking-related events.

In:
• Texas
• Rio Grande
• Migrants

Stephen Smith is a senior editor for CBSNews.com.