A ManTech booth at the Association of the U.S. Army’s 2013 convention in Washington. (Jeffrey MacMillan/For The Washington Post)

ManTech International has acquired Reston cybersecurity firm Knowledge Consulting Group for an undisclosed sum, the company said Tuesday.

The deal is the latest in Washington’s cybersecurity market, which has had a flurry of activity as federal agencies and companies make cyberdefense a priority.

This is also ManTech’s second cybersecurity purchase this year, after its April acquisition of Welkin Associates, a subsidiary of Computer Sciences, for $34 million.

“There is increasing demand for cybersecurity services from both the government and commercial sides,” said William Varner, president and chief operating officer of ManTech’s Mission, Cyber and Intelligence Solutions Group.

Knowledge Consulting Group provides cloud-security services to government agencies including the FBI, the Department of Homeland Security and the Justice Department.

The company is also one of a handful that is certified to audit cloud-computing providers to see whether they meet government security standards. For ManTech, that is a potential growth area, Varner said.

The purchase gives ManTech the ability to expand its work with those agencies and provides access to KCG’s commercial cybersecurity customers, Varner said.

Knowledge Consulting “is a company we have worked with for a long time,” he said. “Together, we will be much more competitive.”

Knowledge Consulting’s 230 employees will join ManTech’s cyber-group. Dusty Wince, the group’s chief executive, will lead ManTech’s efforts to grow its cyber-business, Varner said.

ManTech’s sales in the last quarter were down 18 percent, to $370 million, compared with a year ago. Profit increased to $11.8 million, or 31 cents a share, from $9.6 million, or 26 cents a share.