A bus crash in the Mexican state of Oaxaca killed 16 people on Friday, according to local authorities, who say most of the passengers were migrants. Three children and two women are among the victims, all of whom are from Venezuela and Haiti, the Oaxaca state attorney general said. At least 27 people were injured and transported to nearby hospitals. Pictures posted by authorities on Facebook show the large bus flipped over and heavily damaged on a curve of the mountainous Oaxaca-Cuacnopalan highway. Authorities are investigating the cause of the accident, which took place at 5 a.m. local time (7 a.m. ET). The Oaxaca state attorney general’s office had first said 18 people died in the crash, then revised its count late on Friday evening. The tragedy follows the deaths of at least 10 Cuban migrants, including a child, on Sunday, when the truck they were traveling in also overturned in southern Mexico, according to local authorities. Venezuela and Haiti are sources of large numbers of migrants traveling northward, fleeing insecurity and economic crisis at home. US and Mexican officials have struggled to respond to the arrivals, with Washington putting increasing pressure on Mexico City to shoulder more responsibility for people crossing its territory.