About 21 people have been injured in an explosion that took place in the lower floors of Sandman Signature Fort Worth Downtown hotel, Texas on Monday.

The hotel was operational at the time of the explosion and 26 rooms were occupied. Many people trapped after the explosion in the basement were pulled out by the Fort Worth fire department.

One person was in critical condition and four others were seriously injured in the explosion. All the other injured had minor injuries, MedStar spokesperson said in a press briefing on Monday.

Photos and videos of the site showed windows broken and rubble scattered across the street. The pictures revealed that the nearby shops, restaurants were also damaged by the blast.

A spokesperson of the Fort Worth fire department said a call from the Sandman Signature hotel was received at around 3.35 p.m., local time. After that they received many calls about the explosion.

Upon arrival, the firefighters found the smell of gas spread through the area. The authorities suspect the mishap occurred due to some gas leak.

The police have restricted the area and people have been advised to avoid the area.

The alleged gas-leak is still being investigated and it is not yet confirmed if the source of the leak has been contained or not.

The fire department said on Monday that the blast no longer posed any threat to public safety anymore but they will still surround the area and ensure no one was trapped.