Gov. Martin O'Malley called Northrop Grumman Corp.'s chief executive Friday to make the state's final case for why the giant defense contractor should move its headquarters here, rather than to Washington or Virginia.

Aides did not provide details but said it's a "competitive" offer with incentives such as grants and tax credits.

Northrop Grumman, now based in Los Angeles, has said it is considering locations throughout the D.C. metro area and will probably make a decision in April. It already employs more than 40,000 in the region.