WASHINGTON (Reuters) - Lockheed Martin Corp's agreement with the Pentagon for 32 additional F-35 fighter jets is valued at around $3.8 billion, although the two sides are still finalizing details, a source familiar with the agreement told Reuters.

The price of each of the new planes in the fifth batch of F-35s would be less than 50 percent of the price of the planes in the first batch, said the source, who was not authorized to speak publicly.

(Reporting By Andrea Shalal-Esa; Editing by Gerald E. McCormick)