A fuel truck exploded in a Mexico City maternity hospital on Thursday, killing three people and injuring dozens.

According to Lizbeth Diaz and Joanna Zuckerman Bernstein of Reuters, the victims included one woman and two children. Mexican authorities set up police lines around the chaotic scene, where people seeking information on family members gathered for updates; officials noted that it seemed everyone had been accounted for.

"I am so worried about my sister. She's supposed to have given birth. We brought her in yesterday," Monserrat Garduno, a 32-year-old nurse, said. "They won't let us pass. I want to know how she is."

Reuters reported that several babies were found under the rubble. Mexican firefighters and rescue workers combed through the remains for survivors.

According to Catherine E. Shoichet, Mariano Castillo and Rafael Romo of CNN, more than 100 people were inside Cuajimalpa Maternal Hospital when the blast occurred at 7 a.m., shortly after a hose burst on a truck supplying fuel to the building, triggering an explosion.

"They tried to stop the leak, but it was not possible," Mexico City Mayor Miguel Angel Mancera said, telling Reuters that three people have been detained and two had been hospitalized.

Mancera added that the fuel truck company involved in the blast had been working in Mexico City since 2007. According to Reuters, many areas of Mexico City rely on fuel truck deliveries because they have no mains fuel supply.

Supervising nurse Ivonne Lugo Durantes told CNN that she spent 10 minutes trapped under the rubble before she was rescued. She called her husband, Mario Angeles Sanchez, to describe the events as they unfolded.

"I am still a little bit in shock," Durantes said of the explosion. "It was a nightmare."

According to CNN, Mexican officials initially reported a higher death toll. However, an incorrect report was issued due to a mix-up between the numbers of dead and seriously injured.

Ignacio, a volunteer at the scene, described the rescue efforts to CNN.

"We started pulling babies from the debris who were alive," Ignacio said. "We pulled out, fortunately, I think we pulled out seven. We would've wanted to pull out more."

Witnesses told CNN that "the explosion shook the neighborhood."

"We heard something, and it smelled so much like gas, really a lot," witness Teresa Ramirez said. "Then two minutes, three seconds later, we saw an explosion that made everything fly in the air. It threw me to the ground."

The mayor told CNN that 70 percent of the hospital collapsed, although some walls and steel columns were still standing.

According to CNN, the fuel truck was supplying liquefied petroleum gas to the hospital. The fuel, a mix that could be mostly propane or mostly butane, is commonly used in Mexico for heating, cooking and other applications.