Mexican state-owned oil company Petroleos Mexicanos posted a net loss of 35.95 billion pesos ($2.74 billion) in the first quarter, more than eight times higher than the 4.4-billion-peso loss registered in the same period of 2013.
Pemex made the announcement in a filing Wednesday with the Mexican Stock Exchange.
The company said its before-tax income totaled 174.15 billion pesos ($13.29 billion), down 20.7 percent from the first quarter of 2013.
Between January and March, Pemex's total sales rose to 406.93 billion pesos ($31.06 billion), up 2.6 percent from the same three-month period of last year.
Pemex's tax contributions, which represent about a third of the government's income, fell 6.2 percent annually in the first quarter to 210.11 billion pesos ($16.04 billion).
Mexico's oil production has fallen by nearly a quarter from a high of 3.3 million barrels per day in 2004 due to a sharp decline in output at offshore Cantarell, formerly Mexico's most productive field, and a lack of investment.
To reverse this situation, Mexico enacted an historic energy overhaul last year that ends Pemex's monopoly and will allow private companies to develop crude reserves for the first time since 1938.
Supporters of the overhaul argued that the participation of major multinational energy companies under profit- and production-sharing contracts and licenses is needed to develop promising deepwater reserves in the Gulf of Mexico.
On Wednesday, the Mexican government unveiled a package of legislation to accompany the overhaul, including a bill introduced in the Senate that would reduce Pemex's tax obligations from 79 percent of its revenues to an average of 65 percent.
Finance Secretary Luis Videgaray said of the proposed new tax regime for Pemex that the time has come for the state oil company to be given more autonomy in managing its budget. EFE