HOUSTON, April 30 (Xinhua) -- Three people were injured in a nightclub fire on early Saturday morning in Houston, the largest city of U.S. state Texas, authorities said.

       Over a thousand people escaped a fire at iClub nightclub in southwest Houston, according to the Houston Fire Department.

       Three people were taken to the hospital with smoke inhalation, authorities said. Local media outlet ABC13 reported that cameras caught several people getting oxygen from the firefighters.

       "It took us a while to get here. There was so many people. There was probably 1,000 to 1,500 people trying to exit. Once we got here, we had heavy black smoke coming out of the front door and the rear door," said a spokesperson for the Houston Fire Department.

       The cause of the fire remains unclear. An investigation is underway.