At least 15 people drowned, two survived and nine went missing when a boat carrying Central American migrants capsized off Mexico's Pacific coast, the Mexican Navy said on Saturday.
"We have a total of two survivors rescued and 15 bodies recovered," the Navy said in a statement.
Earlier reports said 24 people had drowned when their boat capsized amid heavy seas churned by tropical storm Kiko, off the coast of southern Mexico.
Rescue operations by Navy ships and helicopters "continue in an effort to locate the nine people who so far have been reported missing," the Navy said.
Since the rescued were Salvadorans and the ship was on a route used by immigrant traffickers to the US, officials believe most of the dead -- eight women and three men -- and the missing were illegal immigrants from Central America, Oaxaca state authorities said in a separate statement.
None of the bodies have yet been identified, officials said.
A TV report said a Guatemalan woman survived from the vessel.
She said it set off from Guatemala on Tuesday with about 25 people on board from Guatemala, El Salvador and Honduras and was wrecked in a storm but she survived by clinging to a barrel.
Residents from a coastal village found the bodies on the beach and picked up others in the ocean with their fishing boats.
The wreck occurred early in the morning near the Tehuantepec Isthmus on Mexico's Pacific coast.
Some 20 migrants from Guatemala and El Salvador died in the same region in a similar accident a few years ago.
Tropical storm Kiko on Saturday was churning in a northwestern direction, packing 200kph winds, the US-based National Hurricane Center said.
The storm is expected to turn toward the Pacific Ocean in the next few days.