(Adds details from report)
MEXICO CITY, April 29 (Reuters) - America Movil, the telecommunications giant of Mexican billionaire Carlos Slim, reported a first-quarter net profit of 19.44 billion pesos ($1 billion) on Monday, up 3.6 percent from the year-ago period and slightly above analysts' average estimate, as lower costs offset declining revenue.
The company's revenue dipped by 3.1 percent to 245.7 billion pesos, below analysts' expectations, hampered by the weakening of currencies in key markets for the company such as Chile's peso and Brazil's real against the Mexican peso.
Costs during the January to March period fell about 6 percent to 170.6 billion pesos.
America Movil said it increased revenue from fixed-broadband internet and mobile subscriptions during the quarter.
Analysts, on average, expected the firm to post net profit of nearly 19 billion pesos and revenue of 250 billion pesos during the quarter.
($1 = 19.4120 pesos at end-March) (Reporting by Julia Love and Noe Torres)