HalliburtonCo. and Baker HughesInc. pledged to fight the U.S. Department of Justice's antitrustlawsuit to stop thepending merger,saying the DOJ has "underestimated the highly competitive nature of theoilfield services industry."

The DOJ filed the suit April 6, alleging that the transaction,valued at $34.6 billion when it was announced in 2014, "threatens toeliminate competition, raise prices, and reduce innovation in the oilfieldservices industry."

Halliburton and Baker Hughes postponed the closing of theirproposed merger and agreed to extend the regulatory approvals until April 30.Extending beyond the stipulated date under the merger agreement, the companiesmay continue to seek relevant regulatory approvals or either of the parties mayterminate the merger agreement, they said in an April 6 news release.

The proposed merger is "pro-competitive" and will providean opportunity for customers "to reduce their cost per barrel of oilequivalent," the companies said.