An explosion rocked the Sandman Signature hotel in Fort Worth, Texas, United States of America on Monday with at least 21 casualties recorded, the New York Times reports.

Although the cause of the explosion could not be immediately ascertained, authorities suspect it was caused by a gas leak after its smell was perceived in the area.

The New York Times reported the police as saying one person was in critical condition and four were seriously injured and 14 people transported to a hospital.   

Speaking at a news conference, a spokesman for the Fort Worth Fire Department, Craig Trojacek, disclosed that there was “a smell of gas in the area.”

“We were getting reports that it had started in the restaurant. We’re not 100 per cent sure that that’s where it actually started at this point,” Mr Trojacek stated.

The Fire Department added that a reunification area had been created in a parking lot a few blocks from the hotel for those in search of their loved ones.

Josh Babb, co-founder of Musume, an Asian restaurant located inside the Sandman, posted on Instagram that three of those injured were its employees.

Governor of Texas, Greg Abbott, said that additional resources could be deployed to the scene, urging “all Texans to pray for those who were injured in the explosion, as well as those bravely responding to keep others safe.”