MEXICO CITY, June 25 (Reuters) - Mexican state energy

company Pemex upped the volume of crude oil it exported in May,

following a substantial dip a month earlier, and returned to

levels closer to its monthly average, official data showed.

Pemex exported 910,801 barrels per day (bpd) in May, up 34%

from April, after it reversed export cuts it had originally

planned to be able to feed its six domestic refineries and the

Olmeca refinery in Dos Bocas.

Its sudden reversal of export cuts for May came after Pemex

had made substantial cuts for April that did go ahead.

Data published by the company late on Monday also showed the

combined processing of its six local refineries in operation

fell in the fifth month of the year to 842,043 bpd, its lowest

level this year.

Even after billions of dollars of investment under current

President Andres Manuel Lopez Obrador, heavily-indebted Pemex is

struggling to maintain the volume of crude oil it refines.

CEO Octavio Romero said on Friday that the new Olmeca

refinery would work at full capacity next month.

However, sources told Reuters that engineers were still

working on key components of the 340,000 bpd refinery, and that

it was far from ready despite multiple promises.

With less being processed at home, Pemex increased its

imports of liquefied natural gas, gasoline, diesel and others in

May to a total of 670,000 bpd, 11% more than in April.

Pemex produced 833,280 bpd of refined petroleum products,

which includes gasoline and diesel but also a lot of fuel oil,

11% less than in April and the lowest this year.

Crude oil and condensate production averaged 1.79 million

bpd for the month, lower than the average for the year so far,

while crude oil production increased slightly to 1.51 million

bpd.