SANTIAGO, Chile — A serious forest fire spread quickly on Chile’s coast Friday and threatened to reach the nearby port cities of Valparaiso and Vina del Mar.

Officials said the fire began at an illegal garbage dump in the afternoon and flames were spread quickly by high winds, leading authorities to declare a state of catastrophe in the area. Deputy Interior Secretary Mahmud Aleuy said that about 4,500 people in six neighborhoods had been evacuated and an additional 10,000 might need to be moved.

Chile suffered its worst urban fire in the same general area, in April 2014, when a raging blaze that started as a forest fire killed 15 people in Valparaiso, injuring more than 500 and destroying more than 2,900 homes.