Fernandez announced Monday plans to seize 51 percent of the YPF shares held by the Spanish energy company. Brufau said Repsol's stake in YPF was worth $10.5 billion.
The announcement was welcomed in Argentina, where citizens blame privatization efforts in the 1990s for a debt default in the early 2000s, the BBC reports.
Brufau, however, was quoted by Bloomberg as saying the move by Fernandez was her "covering up the social and economic crisis Argentina is facing."
The Spanish government said it would take necessary action to protect its business interests overseas. Jose Manuel Barroso, head of the European Commission, was quoted by the BBC as saying he was "seriously disappointed" by the seizure of YPF.
Repsol, in a statement Tuesday, said the "unlawful expropriation" of YPF doesn't affect its growth capacity outside of Argentina.
"Repsol will take all legal measures to preserve the value of its assets and interests of all shareholders," the company said.