Northrop Grumman Corp. was fined $15 million by the U.S. State Department for the illegal export of aircraft navigation software.

Bloomberg News reported government documents show that Litton Industries, which Northrop acquired in 2001, committed more than 100 violations of export law by selling navigation systems to Angola, China, Indonesia and Ukraine all of which, at the time, were prohibited from getting such exports.

The violations included the sale of 73 of the systems between 1994 and 2001 as well as for an additional two years after the Los Angeles-based Northrop acquired the company.

Shares in Northrop closed up 18 cents to $79.12 in trading Thursday.