Troops have been deployed to three airports in Bolivia following a surprise move by the government to nationalise them.
The airports are run by SABSA, a subsidiary of a Spanish company which runs several other airports in other countries.
SABSA was acquired by Abertis-Airports in 2005.
The nationalisation was announced by President Evo Morales on Monday, who ordered the military to take control of the airports.
It was the third nationalisation affecting Spanish investments in Bolivia in less than a year.