(ANSA) - Rio de Janeiro, December 18 - Brazil's anti-trust agency CADE gave Spanish telecom company Telefonica 18 months to reduce its grip on the country's mobile phone market, local media reported Wednesday. CADE had ordered Telefonica to either sell its holdings in the local wireless unit of Telecom Italia, called TIM Participacoes, or find a partner for its Vivo mobile telephone operation. Competition concerns have been raised because Vivo is Brazil's biggest mobile phone provider, while the second biggest is Telecom Italia, a piece of which is owned by Telefonica.