Three petroleum tankers exploded in Abu Dhabi after a fire broke out near Adnoc storage tanks on Monday, leaving three people dead and six injured.
The explosions happened in ICAD 3, Mussaffah, near Mohamed bin Zayed City at around 10am.
Abu Dhabi Police said it resulted in the death of one Pakistani and two Indians and the injury of six others. Their injuries were mild to moderate.
A smaller fire was also reported in the new construction area of Abu Dhabi International Airport.
Emergency services personnel rushed to the scenes. Police later confirmed the fires were brought under control.
Preliminary investigations suggest small flying objects, "possibly related to drones", fell into the areas and started the fires, state news agency Wam reported. Authorities have launched an investigation.
Adnoc said in a statement: "At approximately 10.00am this morning, an incident occurred at our Mussaffah Fuel Depot in Abu Dhabi which resulted in the outbreak of a fire.
"Emergency response teams, including civil defence, fire and ambulance responders as well as an Adnoc emergency response team quickly attended the scene, and the fire was brought under control and extinguished.
"Adnoc is deeply saddened to confirm that three colleagues have died. A further six colleagues were injured and received immediate specialist medical care.
"Professional support teams are supporting the families of all those who have been impacted.
"At this time, the entire Adnoc family extends its deepest sympathy to the family and friends of our colleagues who died this morning.
"We are working closely with the relevant authorities to determine the exact cause and a detailed investigation has commenced."
At the airport, a small fire in an under-construction extension was reported.
Etihad Airways said there was limited disruption to flights. Services soon resumed as normal.
Houthis blamed for deliberate blast
Speaking on Monday night, a top Emirati official said the explosions were a deliberate and "sinful attack on civilian facilities" by Yemen's Houthi militia,
Dr Anwar Gargash, an special adviser to the UAE president, described the group as "terrorist militia" after two blasts in the capital.
Dr Gargash said: "Authorities in the UAE are dealing transparently and responsibly with the sinful Houthi attack on some civilian facilities in Abu Dhabi’."
He went on to say that "the tampering of terrorist militias with the stability of the region is too weak to affect the journey of security and safety that we live in, and the fate of this reckless and absurdity will be demise and defeat".