Firefighters work at the scene of an explosion from a vehicle crash in Ulaanbaatar, Mongolia, on Wednesday. AFP

At least six people were killed including three firefighters after a truck carrying 60 tons of liquefied natural gas exploded in the Mongolian capital of Ulaanbaatar on Tuesday, according to Mongolia's emergency officials.

At least 11 people were injured in the fire near the Dunjingarav market, Mongolia's Emergency Management Office said in a post on Facebook.

More than 600 firefighters and 100 vehicles were involved in putting the fire out, which was eventually extinguished.

"Unfortunately, as a result of the accident, three officers of the 63rd Fire Fighting and Rescue Unit of the National Fire Service were killed while performing their duty," the Emergency Management said in the post on Facebook.

Police officers inspect damage at the scene of an explosion from a vehicle crash in Ulaanbaatar, Mongolia. AFP

According to local online news outlets, the fire quickly engulfed several nearby buildings, including a residential building. Scores of cars were burnt.

"On behalf of the British embassy I extend my condolences to the ... officers who lost their lives during the tragic accident at Dunjingarav," Fiona Blyth, Britain's ambassador to Mongolia said on X.

"Our thoughts are with the families of all those affected and we wish a fast recovery to those injured in this tragic event."

Reuters