Carlyle Group is in advanced talks to acquire ManTech International Corp., a government contractor that also does IT services, according to people familiar with the matter.

The people who asked not to be identified said a deal could be announced this week. The people said the transaction values ManTech at $4 billion.

Talks could still fall apart if an agreement isn't finalized.

Representatives for ManTech and Carlyle could not be reached for comment.

The company's market value was $3.35 billion after ManTech shares closed at $81.97 on Friday.

ManTech provides IT services to the US defense and intelligence agencies.

ManTech was founded in 1968 by George and his partner. He retired from the board in February. He still owns a large amount of the company.

KevinPhillips became CEO and Chairman.

According to its website, Carlyle is an investor in government services companies. The company sold Novetta, one of its portfolio companies, to the company last year.

With assistance by two people.