HOUSTON (AP) -- Halliburton Co., which provides services for the energy industry, said Tuesday that reduced activity by major Mexican customer Petroleos Mexicanos -- Pemex -- will drag down fourth-quarter profit by 2 cents per share.

Customers like Pemex are key since Halliburton relies on international business for the bulk of its income. Houston-based Halliburton said state-owned oil company Pemex decided to reduce activity because of low natural gas prices and other constraints.

Pemex said last week its crude production dropped 7.1 percent in the first 10 months of this year amid declining reserves. Mexico's oil production has been falling as reserves dry up. Pemex said it plans to begin producing oil from promising deep-water deposits in the Gulf of Mexico by 2014.

Halliburton shares fell 81 cents to $29.65 in after-hours trading Tuesday after closing at $30.46, up 2 cents on the day.