A fuel pipeline exploded in a densely populated Nairobi slum Monday morning, killing at least 55 people but likely more, police and Kenya Red Cross officials said.

The explosion apparently occurred about 10 a.m. local time (3 a.m. ET), possibly as a group of people were siphoning fuel from the pipeline, the officials said.

It leveled houses and burned some bodies to dust, said Carol Nduta, a Kenya Red Cross emergency medical instructor and dispatcher who traveled to the scene in Sinai slum, which surrounds the Lunga Lunga industrial area where the pipeline and a fuel depot were located.

“Almost the whole place blew up,” she said.

Police confirmed that at least 55 people died. Nduta said scores more were dead, but their bodies had not yet cooled enough to recover. She said authorities expect to find more bodies in the smoking ruins of homes near the pipeline. Nduta said she believed between 100 and 130 people had died.

An unknown number of injured have been taken to hospitals, particularly Kenyatta National Hospital, Nduta said.

Although some structures continued to smoke and burn Monday afternoon, the fire seemed to be mostly under control, she said.

Nairobi police spokesman Eric Kiraithe confirmed the explosion happened as employees of the Kenya Pipeline Company tried to contain a leak in the pipeline and prevent people from stealing the leaking fuel.

Police didn’t provide a specific cause for the explosion, but Nduta said she understands one of the people trying to siphon fuel from the leaking pipeline was smoking.

Fatalities from fuel leak accidents are common in Kenya .

Scores of residents scramble to scoop up fuel whenever there is a leak or a tanker is involved in an accident. In 2009, more than 100 people were killed when an oil tanker overturned in Molo, in western Kenya. In that incident, someone trying to take some of the fuel lit a cigarette, starting the fire.

CNN’s Andreena Narayan and Faith Karimi contributed to this report.