Spain's Telefonica said Friday it may take legal action against Brazil's anti-trust regulator, which issued a ruling aimed at limiting the telecom giant's holdings in the South American country.

The CADE anti-trust agency ruled earlier this month that Telefonica may not acquire full control of leading Brazilian wireless company Vivo unless it exits its indirect stake in the country's No. 2 mobile operator, TIM Brasil, a unit of Telecom Italia.

In a filing with Spain's CNMV securities regulator, Telefonica said the "remedies imposed" in CADE's Dec. 4 finding were "unreasonable."

In 2010, Telefonica acquired the 50 percent it did not already own in Vivo from Portugal Telecom. The transaction was approved by the Anatel telecoms regulator but Telefonica also needs to get the green light from CADE.

Telefonica then boosted its indirect interest in TIM Brasil when it agreed in September to increase its stake in Telco, the holding company that controls Telecom Italia, to 66 percent.

CADE said on Dec. 4 that it "identified a potential risk to competition, since TIM Brasil and Vivo compete in the market, and with the (2010 transaction) a company (Telefonica) that has a stake in TIM would take over absolute control of Vivo."

Amid the controversy, Telefonica's CEO, Cesar Alierta; and a former chief operating officer, Julio Linares, on Friday decided to resign their seats on Telecom Italia's board, effective immediately.

The decision was made "to reinforce our strong commitment with the previous obligations undertaken by Telefonica to remain separate from Telecom Italia's Brazilian businesses," the filing said.

Likewise, the Spanish company, "without prejudice of any of the rights recognized in Telco's shareholders' agreement, has decided for the time being not to avail of its right to appoint or propose two directors" for seats on Telecom Italia's board. EFE