Bolivian President Evo Morales’ nationalization of three Spanish-owned airports this week has drawn strong criticism from Spain amid strained economic and political ties between the two countries.

Morales charged that the Spanish company Sabsa, which owned airports in the country's major cities of La Paz, Santa Cruz and Cochabamba, had been “maximizing profits” at Bolivia’s expense. In particular, he said Sabsa had failed to deliver promised improvements to its facilities despite reaping more than $2 million in annual profits.

Sabsa, a joint venture between Spanish conglomerate Abertis Infrastructuras SA and Spain’s airport authority AENA, had a contract to operate the airports until 2025.

Morales said Abertis-AENA had promised to invest $26 million in Sabsa from 2006 to 2011, but only ended up putting in $5.6 million, Spanish news outlet EiTB reported.

Abertis, which owns 90 percent of Sabsa, said Bolivia has caused it losses by raising the salaries of airport employees 140 percent since 2005 and by freezing airport tariffs in 2001.

On Monday, Morales ordered police to occupy Sabsa’s offices and instructed the ministry of public works, services and housing to take over operation of the company.

Spain’s Foreign Minister Jose Manuel Garcia-Margallo said his country would “mobilize” its resources and that of the European Union against Bolivia's act of “aggression,” adding that Madrid would have to “rethink bilateral relations as a whole,” Mercopress reported.

Morales said he would hire an independent firm to assess the appropriate amount of compensation for Sabsa’s investors, which would be paid within 120 days.

Since taking office in 2006, the socialist Bolivian leader has expropriated several Spanish companies in the telecommunications, energy and oil sectors.

In December, Morales nationalized two Spanish-owned electrical utilities companies after claiming that they had overcharged customers, and earlier in May he expropriated the subsidiary of Red Electrica, another Spanish energy company.