HOUSTON, Feb. 2 -- Exxon Mobil Corp., the largest U.S. energy company, reported Monday that its fourth-quarter profit fell 21 percent, its lowest level in five years, due to plummeting crude oil prices.

The Texas-based company said in a press release that its fourth-quarter earnings were 6.6 billion U.S. dollars, or 1.56 dollars per share, down from 8.4 billion dollars from the same period in 2013.

The steep fall coincides with a precipitous drop in crude oil prices that rattled U.S. oil companies. Brent crude, the international benchmark, fell more than one third to an average of under 80 dollars per barrel in the final three months of 2014.

For the full year, Exxon earned 32.5 billion dollars, down from 32.6 billion dollars in 2013. The marginal drop, the company said, reflects "the strength of its integrated business model in a lower-price environment."

Exxon has not announced if it will cut its current 38.5 billion dollars capital budget. But it did say Monday that it would cut spending on share buy-backs by two-thirds to 1 billion dollars this quarter as it searches for ways to cut costs.

Other super-majors have already announced budget cuts on weaker profits. Royal Dutch Shell PLC has said it would spend 15 billion dollars less than planned over the next three years. And Chevron Corp. plans to cut spending by 5 billion dollars from 2014 and suspend its share-buy-back program.