At least eight migrants were found dead in the Rio Grande—on the Mexico-US border—after dozens attempted a hazardous crossing near Eagle Pass, Texas, US officials said Friday, AP reported.

US Customs and Border Protection (CBP) and Mexican officials made the discovery Thursday while responding to a large group of people crossing the river following days of heavy rains that had resulted in particularly swift currents. US officials recovered six bodies, while Mexican teams recovered two others, according to a CBP statement.

The agency 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 continue searching for any possible victims, the CBP said.

CPD did not say what country or countries the migrants were from, and did not provide any additional information on the rescue or search.