Oil services company Halliburton said Monday profits were hit by an industry downturn, but the pending acquisition of rival Baker Hughes should provide a boost.

Halliburton said total revenue for first quarter of 2015 was $7.1 billion, a 4 percent decline year-on-year. The company blamed the slowdown on a "challenging commodity price environment" and a significant decline in activity in the exploration and production sector of the energy industry.

Baker Hughes said Friday the number of rigs in service worldwide fell by about 1.8 percent from March to 1,251 for the week ending April 10. In the United States, the rig count is down nearly 4 percent to 988. Crude oil, meanwhile, continues to trade in a bear market, with key indices down about half from the June 2014 levels.

"Our global customer base has responded by lowering activity levels and seeking price concessions, which has impacted our margins," Chairman and Chief Executive Officer Dave Lesar said in a statement.

Lesar said there's been an "unprecedented decline" in North American drilling activity during the first quarter, with the U.S. rig count falling by 21 percent year-on-year. The pressure should continue for at least the medium-term, he said.

Halliburton in January said it was adjusting its workforce in Texas as it worked to streamline operations in the weakened market. Schlumberger, the world leader in oil services, said last week its combined staff reductions so far this year represent about 15 percent of its workforce.

Halliburton made a move to acquire Baker Hughes in November. Lesar at the time said the combined company would create a "bellwether global oilfield services company" that would trade under the Halliburton ticker, HAL.

"We are excited about the pending Baker Hughes transaction, which will significantly enhance the growth potential of our organization as we combine our highly complementary suites of products and services into a comprehensive offering that will deliver an unsurpassed depth and breadth of solutions to our customers," he said in his latest statement.

Halliburton under the terms of the deal buys all outstanding shares in Baker Hughes for $34.6 billion. The deal is expected to close by the end of the year.