At least eight migrants were found dead in the Rio Grande in Texas after dozens attempted a hazardous crossing near Eagle Pass.
US Customs and Border Protection (CBP) and Mexican officials made the discovery while responding to a large group of people crossing the river following days of heavy rain that had resulted in particularly swift currents.
American officials recovered six bodies, while Mexican teams found two others.
The CBP said US crews rescued 37 others from the river and detained 16 more, while Mexican officials took 39 migrants into custody.
Officials on both sides of the border are continuing to search for any more possible victims.
The Border Patrol’s Del Rio sector, which includes Eagle Pass, is fast becoming the busiest corridor for illegal crossings. Agents stopped migrants nearly 50,000 times in the sector in July, with Rio Grande Valley a distant second at about 35,000.
The area draws migrants from dozens of countries, many of them in families with young children. About six in 10 stops in the Del Rio sector in July were migrants from Venezuela, Cuba or Nicaragua.
The sector, which extends 245 miles along the Rio Grande, has been especially dangerous because river currents can be deceptively fast and change quickly. Crossing the river can be challenging even for strong swimmers.
US officials announced last month that they had discovered the bodies of more than 200 migrants in the sector from October to July.