WASHINGTON ― An affiliate of government contractor Amentum will buy DynCorp International, the global services provider, the companies announced Thursday. The deal, for undisclosed terms, is expected to close in the fourth quarter of this year.

In a joint release, the companies billed the deal as creating a mission-critical support services powerhouse, as they have had, collectively, $6 billion in revenue over the last 12 months. The new entity would employ 34,000 people in more than 30 countries.

“The combination of our two companies will accelerate our growth into key new markets such as aviation support services, contractor logistics support, intelligence solutions, and training,” said Amentum CEO John Vollmer.

Earlier this year, Amentum launched as a privately held company after the sale of the AECOM Management Services business to affiliates of Lindsay Goldberg and American Securities LLC. The new firm provides mission support and equipment sustainment, information technology, intelligence, nuclear and environmental remediation, among other services.

“We look forward to welcoming DynCorp’s employees to the Amentum family," Vollmer said. "Our complementary capabilities and cultures will propel Amentum to the top of our market as a leader with differentiated solutions to support our clients' most challenging missions.”

In April, DynCorp won a $185 million, nine-month extension to support Army Sustainment Command in Southern Afghanistan under the Logistics Civil Augmentation Program (LOGCAP) IV contract. The company said it has continuously provided LOGCAP services for the U.S. Army for 11 years.

“This strategic combination of two market leading companies will deliver tremendous value to our customers and increased opportunities for our employees,” said DynCorp CEO George Krivo.

Amentum is based in Germantown, Md., and DynCorp is based in McLean, Va.