Spain's Telefonica, Europe's second-largest phone company, said Thursday its net profit more than doubled in the first quarter thanks to a one-off financial boost from the sale of its British unit O2.

The carrier posted a forecast-beating net profit in the period of 1.8 billion euros ($2.0 billion) up from 688 million euros during the same time last year.  

Analysts contacted by financial information services provider Factsheet had predicted a first quarter result of 669 million euros.

Telefonica in March sold British telecom giant O2 to Hong Kong group Hutchison Whampoa for 14 billion euros.

Proceeds from the sale of O2 have been largely earmarked to reduce Telefonica's debt pile which stood at 45.6 billion euros at the end of March.

The company, with operations across Europe and Latin America, said its sales rose 12.6 percent to 11.54 billion euros as growth in Germany offset weakness in Brazil and a further contraction of its domestic market.

Revenues in Germany jumped 69.4 percent thanks to the acquisition of E-Plus and a "significantly higher contribution of handset revenues", it said in a statement.

Revenues in Spain, which is struggling with a jobless rate of 23.8 percent, fell 3.8 percent while in Brazil they inched up by 4.8 percent.

Brazil, Germany and Spain account for 66 percent of Telefonica's sales.

Shares in Telefonica fell 0.75 percent to 13.20 euros in early morning trade while the Ibex-35 index of most trade Spanish shares was flat, down 0.05 percent.