Bolivia's President Evo Morales has joined a street football match to protest against Fifa's ban on international games at high altitude.
Mr Morales said that if he and his ministers could play at more than 2,500m (8,200ft) above sea level, so too could the world's elite players.
Fifa says high altitudes may harm player health and distort competition.
Mr Morales has called a meeting of officials from Latin American countries that play their home games at altitude.
BBC Americas editor Will Grant says the Bolivian president is an avid football fan and a keen player and there is little doubt he will take his fight against the ban as far as possible.
Mr Morales took to the pitch 3,600m (11,811ft) above sea level - in front of the government palace in the capital, La Paz - to prove his point, and played four games of football.
"It is possible to play soccer just as much at high altitudes as low altitudes and we hope that this demonstration of officials and members of the national selection [shows that]," Mr Morales said.
"We hope they put their hands on their hearts to consider that this error discriminates and marginalises sport at altitude."
"Without sport - without football - there cannot be South American unity," Mr Morales said.
LATIN AMERICAN CITIES
Bolivia: La Paz - 3,600m (11,811ft)
Ecuador: Quito - 2,800m
Colombia: Bogota - 2,640m
Peru: Cuzco - 3,500m
"It is not possible that through some shady actions of Fifa we will see the division of South America and the division of Latin America."
In Ecuador, the mayor of Quito called for a rally to protest against the decision.
Hundreds of people exercised in the centre of Quito to show, they said, that there were no health risks.
Luis Eduardo Garzon, the mayor of a similarly affected city, Bogota in Colombia, pledged to climb the 3,300m Monserrate peak to show altitude held no dangers.
All the affected nations deny they have used high-altitude grounds to gain a competitive advantage.
Inca Garcilaso de la Vega stadium in Cuzco, Peru, would be too high
Fifa's ruling has incensed many in Bolivia in particular.
La Razon newspaper has vowed to deluge Fifa president Sepp Blatter with one million protest letters.
Fifa officials will hear the protests of the affected nations at a 14 June meeting in Asuncion, Paraguay.
Before that Mr Morales has called a "unity" meeting of affected cities and nations for 6 June in La Paz.
Peruvian and Bolivian soccer officials laid the blame for the decision on Argentina, Brazil and Uruguay, although Mr Morales said the presidents of Argentina, Uruguay and Venezuela supported his campaign.
The team doctor of the Peruvian national team, Javier Arce, said matches should also be banned at hot and humid venues in lower-lying countries.
But Kleber Leite, vice president of the Brazilian club Flamengo, said the ruling was "a victory for humankind".
The Argentina Soccer Association said it believed altitude caused "headaches, dizziness, nausea, gastrointestinal problems and fatigue".