Ash from Chile's Puyehue volcano grounded flights Tuesday at airports in the capitals of Uruguay and Argentina, officials said.
In Buenos Aires, both the international airport Ezeiza and the mostly domestic service airport Aeroparque shut down as ash was detected in the air and on the tarmac, said a spokesman with Aeropuertos 2000.
Most airlines decided to cancel flights at least through Wednesday morning, the Argentine spokesman said.
At least 15 flights were canceled Tuesday in neighboring Uruguay, officials at Carrasco international airport said.
The Puyehue volcano has been causing air travel mayhem since it rumbled back to life on June 4 for the first time in five decades, belching into the air an untold volume of dust and ash.
Flights across South America — including hubs in Montevideo, Chile's capital city Santiago and southern Brazil — have all been hit as ash clouds swept around the southern hemisphere to linger over Australia and New Zealand.
The Puyehue volcano is high in the Andes mountains, 870 kilometers (540 miles) south of Santiago near the border with Argentina.
