The death toll from an explosion in Mexico City has risen to 32, the head of the country's oil giant Pemex said.
The blast hit the headquarters of state-run Pemex on Thursday afternoon, local time, shattering the lower floors of its downtown tower and sending frightened workers running outside.
More than 100 people were injured, and emergency workers continue to look for more people trapped in the rubble.
Emergency services workers worked through the night in Mexico City, to search for people trapped in rubble after an explosion hit the headquarters of state-owned oil company Pemex.
Mexican president Enrique Pena Nieto vowed to "work exhaustively to investigate exactly what took place, and if there are people responsible, to apply the force of the law on them."
The blast happened in mid-afternoon local time on Thursday.
The death toll rose to 25, and over 100 were thought to be injured.
Shortly after midnight local time, the company said that at least 46 people were still being treated in hospital.
Pemex said the blast would not affect operations.
The state-owned oil provider has been hit by several other safety incidents in recent years.
Soldiers joined emergency rescue teams to search for people feared trapped under debris after an explosion in Mexico City.
The blast in a neighbouring building hit the headquarters of state-owned oil giant Pemex, killing at least 25 people and injuring more than 100.
Interior Minister Miguel Angel Osorio Chong told Reuters that the number of casualties is expected to rise.
He said at least one person had been pulled out alive.
A paramedic at the scene told Reuters that as many as 100 people could be trapped.
The blast happened shortly before many workers were due to end their shifts at Pemex, making the area particularly busy.
Mexico's interior ministry has said that the death toll from a powerful blast that rocked the Mexico City headquarters of state-run oil giant Pemex on Thursday had climbed to 25.
Emergency services are responding to an explosion at the headquarters of oil company Pemex in Mexico City. Officials say 14 people died and 100 were injured in the blast at the tower block. It is not yet clear what caused the explosion.
A powerful explosion rocked the Mexico City headquarters of state oil giant Pemex killing at least 14 people and injuring 100 others.
The blast hit the lower floors of the tower block, throwing debris into the streets and sending workers running outside.
Interior Minister Miguel Angel Osorio Chong said the blast killed at least 14 people and injured 100. It was not yet clear what caused the explosion, and the death toll could still rise, he added.
"The place shook, we lost power and suddenly there was debris everywhere. Colleagues were helping us out of the building," witness Cristian Obele told Mexican television.
President Enrique Pena Nieto said via Twitter he "deeply regretted" the deaths and headed to the scene of the blast.
The Mexican Interior Minister Miguel Angel Osorio Chong says 14 people were killed in an explosion at Mexican oil giant Pemex's Mexico City headquarters and 80 were injured, reports Reuters.
The death toll could still rise, he told local television.
An explosion has rocked the ground floor of the Mexico City headquarters of state oil company Pemex, killing one and injury many others, according to local media.
The building is understood to have been evacuated did it is not yet clear what caused the explosion.
Mexican television images showed debris scattered near the base of the skyscraper and injured people being taken out on stretchers.Local media are reporting 22 people had been injured in the explosion and that one person had died in the building.
Plaster had fallen from the ceiling of the basement, and the situation at the Pemex tower was "delicate," a spokesman for local emergency services said.