Clouds of ash spewing from Chile's Puyehue volcano have grounded flights at airports in the capitals of Uruguay and Argentina, where a major football tournament is being held.
Scores of local and international flights were delayed or cancelled in and out of Buenos Aires, regional airport authority Aeropuertos Argentina 2000 said on its web page.
The Puyehue 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 a huge volume of dust and ash.
Flights across South America - including hubs in Montevideo, Chile's capital city Santiago and southern Brazil - have been hard hit as ash clouds swept around the southern hemisphere to linger over Australia and New Zealand.
The flight disruptions on Friday wreaked havoc for football fans arriving in Argentina for the July 1-24 Copa America competition, which has been drawing thousands of supporters. The regional tournament is being played in several Argentine cities.
In nearby Montevideo, more than 20 flights were cancelled due to the ash clouds, officials at the Carrasco International Airport said. Most of the flights were to or from Buenos Aires, but departures for places like Lima and Porto Alegre in Brazil were also cancelled.
Weather experts at the airport said flights will likely remain grounded for the rest of Friday.
Provinces in southwestern Argentina, including Rio Negro and Neuquen, are in a state of emergency due to widespread damage caused by a massive layer of volcanic ash from the Puyehue.
The Puyehue volcano is high in the Andes mountains, 870km south of Santiago near the border with Argentina.