Increased activity at a volcano on the border of Chile and Argentina has authorities in both countries on alert, according to AP. The Copahue volcano in Argentina's Neuquen province and Chile's Biobio region began spewing ash and gas early Saturday, but officials say it's still in an early eruption stage. Chile's Mining Minister Hernan de Solminihac says the volcano's smoke plume led Argentine emergency officials to issue a yellow alert and constantly monitor its activity in case of a full eruption. Flights expected to pass by the area around the volcano have been warned. Officials say there's no need yet to evacuate people near the volcano, which is part of the Andes mountain chain. A volcano in southern Chile erupted last year, forcing the cancellation of hundreds of flights and the evacuation of more than 600 people.