Mexico City, Mexico (CNN) -- A second person survived a massacre in which 72 migrants from Central and South America were killed last week in northern Mexico, Ecuadorian President Rafael Correa and Mexican officials said.
A man from Ecuador was previously thought to be the only survivor.
That man, identified as Luis Freddy Lala Pomavilla, said someone else also lived through the mass shooting, Correa said at a news conference late Tuesday night upon his return to Ecuador from a trip to Haiti.
Correa did not provide details other than to say the second survivor came from Honduras.
"We don't want to put him in danger," Correa said.
Viviana Macias, a spokeswoman for the Mexican attorney general's office, confirmed Wednesday that a second person had survived the attack.
The attorney general's office said authorities had not revealed news of the second survivor in order to protect the person's safety. For the same reason, officials said Wednesday, they will not reveal the person's identity.
The attorney general's office said in a release Wednesday afternoon that the survivor is being held and protected as a witness and has given officials "relevant information to identify those presumed to be responsible." The agency has been in touch with authorities in Honduras, the release said.
Lala Pomavilla, the Ecuadorian survivor, was returned to his homeland late Sunday.
The young man was wounded in the attack and said he survived by playing dead. He later walked several miles to a military roadblock near the town of San Fernando in Tamaulipas state, less than 100 miles from the U.S. border.
Officials are investigating whether members of the Zetas drug cartel were responsible for the deaths.
The bodies of the 72 victims are being returned to their homelands, which include Guatemala, El Salvador, Honduras and Brazil.
Mexican officials returned the remains of 16 migrants to Honduras on Wednesday.
A live broadcast on CNN affiliate Televicentro showed six-man honor guards wheeling the bodies one by one off a transport aircraft. Bereaved relatives and friends cried and held each other as the gray caskets glided by slowly, guided solemnly by soldiers in dress uniforms and red-plumed hats.
The caskets, each adorned with a bouquet of flowers on top, were placed under a large tent on the tarmac at the air force airport in Tegucigalpa, the capital of Honduras.
"Repatriation," said the Televicentro banner imposed over the bottom of the TV image. "What started as a search for the American dream ended in a mortal nightmare."
After the 16 caskets were gathered in the tent, a Roman Catholic priest prayed over them.
"Don't lose your faith in God," he told those gathered there before he sprinkled holy water on each of the caskets.
Honduran President Porfirio Lobo also addressed the crowd, merely reading the names of the 16 victims before walking back to his spot in a line of dignitaries.
Some family members were brought up to have a word with Lobo, who hugged them and spoke quietly with them.
The caskets were released to the families after the ceremony, and at one point Lobo went to where a man with a gray New York Yankees cap was sobbing as he leaned on a coffin. Lobo patted the man on the shoulder and reached out to a woman standing next to him.
The victims will be taken to their hometowns for burial.
CNN's Jose Antonio Flores, Krupskaia Alis and Arthur Brice contributed to this report.