UPDATE 2-Argentina's YPF H1 net profit falls to 2.13 bln pesos

* Government seized control of YPF during the 2nd quarter

* Argentina says striving to regain energy self-sufficiency (Adds details, bullet points)

BUENOS AIRES Aug 10 (Reuters) - Argentina's state-controlled energy company YPF reported a first-half net profit of 2.13 billion pesos ($462 million), down from a net profit of 2.75 billion pesos in the same 2011 period, the company said on Friday.

Buenos Aires-based YPF issued a statement that did not offer an explanation for the fall.

The government seized control of YPF from Repsol during the second quarter of the year, accusing the Madrid-based parent company of under investing in Argentine production.

Argentine President Cristina Fernandez easily won re-election last October, promising to increase state involvement in Latin America's No. 3 economy.

The 59-year-old Peronist leader is part of a bloc of regional governments - including Venezuela, Ecuador and Bolivia - bent on regaining control of their natural resources from foreign companies.

The Fernandez administration, also on Friday, ordered a tax hike on biodiesel exports, a move it said was needed to bring down domestic fuel prices.

YPF on Thursday opened a diesel fuel refinery near the city of La Plata that is expected to produce 1.75 billion liters per year as part of Argentina's plan for regaining energy self-sufficiency after years of rising fuel imports. (Reporting By Magdalena Morales, writing by Hugh Bronstein; Editing by Gary Hill, Leslie Gevirtz and Bob Burgdorfer)