Saturday, April 21, 2012
20 April 2012 Last updated at 20:54 GMT
Members of the European Parliament have condemned Argentina's decision to nationalise the Spanish-controlled oil company YPF. They said the move was "an attack on the exercise of free enterprise".
They also demanded that the European Commission take action against Buenos Aires at the World Trade Organization.
Spain meanwhile announced its first retaliatory step, saying it would promote Spanish biodiesel fuel production to reduce Argentine imports.
Deputy Prime Minister Soraya Saenz de Santamaria said Spain was considering further political and diplomatic measures in retaliation for Argentina's decision to take control of 51% of YPF.
Argentine officials have said they are not worried about possible reprisals.
Argentine President Cristina Fernandez de Kirchner announced the measure on Monday, saying she was asserting sovereignty over Argentina's energy resources.
The move has wide support in Argentina but has provoked outrage in Spain, which has threatened reprisals.
Repsol has said it wants around $10bn for its stake in YPF, but Argentina has said it does not accept that valuation.
It says YPF did not invest enough to increase output from its oil fields, forcing Argentina to rely on imports.
YPF, Argentina's biggest oil company, was privatised in 1993.
Last year it announced huge new finds of shale oil and gas.