An explosion heard at least a kilometre away sent debris flying across one of Abu Dhabi's busiest roads on Monday, killing two people and destroying two fast food restaurants. A video showing the aftermath of the explosion, which authorities said was caused by a gas leak that ignited at around 10am, revealed the extent of the damage. It showed cars parked nearby Hardee's and KFC on Sheikh Rashid Bin Saeed Road – known locally as Airport Road – having been pushed by the force of the blast, which also blew out the concrete walls of the fast food chains. The windows of the residential flats on the two floors directly above the restaurants were shattered as the sound of many sirens rang out. Ritchelle Otrillo, 40, a saleswoman who works at a haircare shop two buildings from the accident site, said she heard a loud bang at around 10am. "I went out to see what happened, and I saw people covered in blood "I had four customers, and one customer said she had just left with her kids from KFC five minutes before, and she was almost crying. She was very lucky, she said God saved her." Police advised Ms Otrillo to close the shop and go home. It was reopened at 7pm once the area was cleared by authorities. "This is the first time I have seen something like this," she said. A video, taken by a resident in the opposite building, showed smoke rising over the damaged tower and traffic being redirected by police. Curious passers-by were kept at a distance for their safety as civil defence teams moved to clear the area. Two people died in the explosion, officials said. "Unfortunately, two victims lost their lives – one near the site of the incident, and a second passer-by who was hit by debris," Abu Dhabi Government Media Office said. "We extend our heartfelt condolences to their families, God rest their souls." Police quickly evacuated the area of residents and conducted a "comprehensive check up of the building and neighbouring buildings" to ensure that there were no further injuries. Investigations revealed that the explosion was caused by a misalignment in the gas container fittings following refuelling in a residential building. Damage was contained to the restaurants on the ground floor and a neighbouring building, authorities said. The roads leading to the block were closed until 6.30pm, when police said the area was safe again.