Boeing won a $3.48 billion contract Friday to retain its leading role in building a US shield against long-range ballistic missiles, defeating rival Lockheed Martin Corp., officials said Friday.

The US Missile Defense Agency announced the decision for the seven-year contract in which Boeing will test, engineer and manufacture the system designed to thwart potential attacks from intercontinental ballistic missiles.

Chicago-based Boeing was joined by partner Northrop Grumman, which will oversee the ground system and other aspects of the project, Boeing said in a statement.

Boeing offered "innovative solutions and a cost-effective approach to program management and execution," said Dennis Muilenburg, president and CEO of Boeing Defense, Space and Security.

Lockheed, based in Bethesda, Maryland, had hoped to edge out Boeing, which has been the prime contractor for the anti-missile program since 2001.

The ground-based mid-course missile defense system has had a mixed record on missile tests, with two failures in 2010. The program has also faced cost overruns due to faulty parts, and the Pentagon is now requiring contractors to absorb the cost of defects in the future.