The death toll from an explosion that ripped through a petrochemical plant on Mexico's southern Gulf coast has risen to 24, state oil company Petroleos Mexicanos has said.
Pemex raised the toll from the 13 fatalities previously known and said eight workers remained missing. It also said 19 people remained in hospital, with 13 in a serious condition.
In a statement, the company said 12 of the bodies had been identified and eight released to family members.
Earlier, President Enrique Pena Nieto toured the plant in the industrial port city of Coatzacoalcos and met relatives desperate for word on the fate of still-missing loved ones.
"I understand the anxiety, the worry, the anguish you are going through," Mr Pena Nieto said, assuring them that both Pemex and the Mexichem company, which jointly operated the plant, would fulfil their responsibilities and compensate those hurt by the accident.
About 30 families gathered at a plant entrance road, where a sharp chemical smell still hung in the air about a mile from where the explosion occurred on Wednesday afternoon. Many wore facemasks to ward off the pungent odour.
Scuffles broke out as people unsuccessfully tried to force their way into the installation. Some shouted at marines and soldiers who were called in to guard the facility and threw rocks at a government SUV when it arrived at the scene.
Rosa Villalobos travelled about four hours by bus from the city of Veracruz to scour Coatzacoalcos hospitals looking for her son, Luis Alfonso Ruiz Villalobos, a 25-year-old worker at the plant.
"What I want is for justice to be done in my son's case, for there to be no impunity," she said. "I'm going to stay here. Even though I have no money, even though I have nothing to eat, I'm staying put."
Some volunteers brought food and drink to the families. After a while authorities began taking people inside in small groups to see a list of those confirmed dead. Some left crying after seeing their loved ones' names.
Pemex said Thursday night that it was prioritising the safety of those inspecting the plant and teams were still gradually gaining access to more parts of the site.
The blast forced evacuations of nearby areas as it sent a toxin-filled cloud billowing into the air and injuring more than 100 workers.
Jose Antonio Gonzalez Anaya, Pemex's director, told Radio Formula that the explosion was caused by a leak of an as-yet unknown origin.
Antonio Mariche, who accompanied the Villalobos family in search of Luis Alfonso, vowed that the families would demand a full account of what happened.
"To the president, to the state governor, to the head of Pemex, we will not allow any more cover-ups like have happened with previous accidents," Mr Mariche said.
"They have covered up the numbers (in the past); there have been people who disappeared and regrettably never appeared. We will go to the last consequences to make sure this doesn't keep happening."
The Clorados 3 plant of Petroquimica Mexicana de Vinilo, where the explosion happened, produces the hazardous industrial chemical vinyl chloride.
In early February, a fire killed a worker at the same plant.