Oilfield service company Halliburton Co posted a drop in quarterly profit on Monday, hit by declining spending by energy producers, and warned that the outlook for the coming quarters looked weak.

U.S. natural gas prices have sunk to a more than six-year low recently, and crude oil prices are down by two-thirds from their highs last year, prompting energy companies to scrap some projects and slow spending on others.

These industrywide declines have been exacerbated by restrictions to some of our customers' access to capital and the decrease in global demand for oil and natural gas, Halliburton Chief Executive Dave Lesar said in a statement.

Halliburton's smaller peer, Weatherford International Ltd , also saw its profits sink from a year earlier, even though revenue climbed as its Latin American business nearly doubled.

Shares of both companies fell nearly 6 percent in premarket trading.

Much of the industry weakness has been in North America, where low energy prices have resulted in the idling of about one-third of the rigs used to drill for gas and oil. Analysts expect more of those rigs to stop working in the coming weeks as gas prices remain low.

EARNINGS HIT

Halliburton's first-quarter net profit before items fell to $378 million, or 42 cents per share, from $575 million, or 64 cents per share, a year earlier. Revenue fell 3 percent to $3.9 billion.

Excluding a charge of $28 million for cutting jobs, the world's No. 2 oilfield services company behind Schlumberger Ltd posted earnings of 44 cents per share, according to Reuters Estimates, topping the analysts' average forecast of 41 cents.

Last week, Nigeria's justice minister said the he would prosecute any state officials found to have taken bribes from Halliburton's KBR unit, which has been split off into a separate company.

KBR pleaded guilty in February to charges that it paid $180 million in bribes in the country to obtain rights to construct an energy facility.

Weatherford's first-quarter earnings fell to $165 million, or 23 cents per share, from $264 million, or 38 cents per share.

Excluding a charge from an investigation, costs to exit some sanctioned countries and job cuts, Weatherford's earnings per share of 27 cents fell short of the analysts' average forecast of 29 cents.

A boost in the Weatherford's Mexico contracts helped the company lift its revenues by 3 percent to $2.26 billion in the quarter.

Halliburton shares were down 5.7 percent at $17.71 in trading before the market opened, while Weatherford fell 5.8 percent to $13.89.

(Reporting by Matt Daily in New York and Braden Reddall in San Francisco; Editing by Lisa Von Ahn)

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