MONTERREY, Mexico (Reuters) - The first hurricane of the eastern Pacific season barreled toward the southern coast of Mexico on Sunday, packing maximum sustained winds of 75 mph (120 km/h) that are expected to strengthen before it makes landfall on Monday.

       As of 7 a.m. Sunday (Mexico City time), Hurricane Agatha was located about 200 miles west south west of Puerto Angel, according to the National Hurricane Center (NHC).

       Hurricane warnings have been declared for parts of the coast of Oaxaca, stretching from Salina Cruz to Lagunas de Chacahua, according to the NHC.

       The storm is expected to bring heavy rainfall to the southern states of Oaxaca, Chiapas, and Guerrero by Sunday afternoon, the NHC said, which could spark "life-threatening flash flooding and mudslides."

       (Reporting by Laura Gottesdiener in Monterrey; Editing by Mark Porter)