Dominican authorities announced Tuesday that at least 13 people were killed and more than 70 others were injured when the roof of a nightclub collapsed in the capital, Santo Domingo.Director of the Emergency Operations Center Juan Manuel Mendez, said that rescue teams have begun searching for survivors under the rubble of the collapsed roof, stressing that there is hope of finding more survivors.Mendez added that search and rescue operations will continue until it is confirmed that no one is under the rubble.The causes of the roof collapse have not yet been determined.