The main airports in Argentina and Uruguay were up and running again Monday, but officials warned that continuing eruptions from neighboring Chile's Puyehue volcano could disrupt air travel for months to come.

Chile's Sernageomin mining and minerals authority said in a report issued Monday that the ash and dust that has intermittently darkened the region's skies over the past few months were likely to continue "given the characteristics of the present volcanic activity."

The study, which followed weekend disruptions caused by ash from the Chilean volcano, concluded that air traffic disruptions from Puyehue "could continue for months" depending various conditions, including wind speed and direction.

Meanwhile, Argentina officials on Monday said the dust cloud had dissipated enough to resume flights.

"There is no ash. The weather conditions improved and there are no particles on the surface," said a spokesman for Aeropuertos 2000, which operates the two major airports in Buenos Aires.

Later in the day, airlines in Uruguay also took to the air again, after being prevented from doing so by ash from the Chilean volcano.

"Most flights are now operating" between the two countries, an official at Montevideo's Carrasco International Airport told AFP.

Brazilian airlines GOL and TAM said they too had resumed flights to Argentina. GOL said it also has resumed flights to Uruguay, but TAM said its flights to the country were still suspended.

Air traffic in the southern hemisphere has been hit hard in recent months. Airports in Buenos Aires and Montevideo and later those in Australia and New Zealand were paralyzed when the volcano high in the Andes roared back to life in June after sleeping dormant for half a century.

Since June most airports in Argentina have been forced into shutdowns at some point due to dangerous ash threatening the safety of commercial airliners.

Ash poses a significant threat to aircraft because once sucked into engines, it can be transformed into molten glass by the high temperatures and potentially cause an engine to fail.