Adds details on GM's talks with RTX, L3Harris in paragraphs 5-7

By Kalea Hall

DETROIT, June 16 (Reuters) - General Motors GM.N and defense company Lockheed Martin LMT.N are collaborating on projects to strengthen the U.S. manufacturing and defense industrial base, the companies said Tuesday.

GM Defense, the automaker's defense business unit, and Lockheed said the U.S. Department of Defense facilitated their partnership due to the growing demand for additional production capacity for defense products.

In a statement, the companies did not specify projects they will work on, but said they will focus on three key areas: improving production readiness, strengthening supply chains and applying advanced manufacturing and design approaches to increase efficiency.

Bruce Brown, head of strategy for GM Defense, said the company will look at using its labs and production facilities for the partnership.

GM has also held talks with defense contractor RTX RTX.N, a source familiar with the matter said on Tuesday.

Bloomberg News reported earlier on Tuesday that GM was in discussions with RTX and L3Harris LHX.N about helping the weapons makers boost production, with any tie-up expected to involve work similar to its Lockheed deal.

RTX declined to comment. GM and L3Harris did not immediately respond to requests for comment on the Bloomberg report.

GM is investing $9 billion in capital and $7 billion in research and development in its overall business this year, but has not said how much it is investing in the GM Defense business.

Lockheed is investing $9 billion through 2030 to scale munitions production and upgrade facilities.

Frank St. John, Lockheed's chief operating officer, said it was too early to say what projects it would invest in with GM Defense.

Crosstown rival Ford Motor F.N has said several governments in Europe and North America have discussed with the company how its products can support defense departments.