Authorities have said that at least seven people were killed in a natural gas explosion at a maternity and children’s hospital just outside Mexico City.

Early reports said that three people were killed in the blast on Thursday. However, CNN noted that government and emergency officials now say at least seven people, including four children, are dead and the death toll could rise.

The Los Angeles Times reported that in addition to those killed, more than 50 others were injured in the explosion. At least 22 of them are children and 32 are adults.

Officials said it is believed at this time that a gas tank burst, which triggered the explosion and caused anywhere between 30 and 40 percent of the hospital to collapse. Rescue efforts are underway to free anyone who may be trapped in the ruins.

Mexican television showed several images of the damaged hospital and pictures of the aftermath were shared on social media as well.

The government-run facility mostly serves middle and low-income families.

images shared via Twitter by Cinco Radio and CIUDAD.