Last checked at 
(Adds comment from Lockheed executive, updates stock price,adds analyst comment)
WASHINGTON, Dec 12 (Reuters) - Donald Trump on Mondaycriticized Lockheed Martin's F-35 fighter jet program as tooexpensive, the latest attack by the U.S. President-elect onlarge defense contractors.
The aerospace giant's shares dropped 4 percent after Trump'stweet, while shares of several other defense contractors alsoweakened.
"The F-35 program and cost is out of control," Trump said onTwitter. "Billions of dollars can and will be saved on military(and other) purchases after January 20th."
Last week, he also used Twitter to target Boeing Co for its "out of control" costs on a new fleet of Air Force Oneplanes, urging the federal government to "Cancel order!"
Lockheed Martin's F-35 program leader, Jeff Babione,responded by saying the company understands concerns aboutaffordability and has invested millions of dollars to reduce thejet's price.
Babione said Lockheed's goal was to reduce the price of theF-35 by 70 percent from its original estimates. "We project itto be about 85 million dollars in the 2019 or 2020 time frame,"he told reporters in Israel.
A week before Trump won the Nov. 8 presidential election,the U.S. Defense Department and Lockheed Martin concluded negotiations on their ninth contract for 90 F-35fighter jets after 14 months of negotiations, the Pentagon said.
Lockheed won the contract, valued at up to $7.18 billion, inlate November and has received an interim payment.
Trump campaigned on a promise to cut waste in federalgovernment.
Lockheed and its key partners, Northrop Grumman Corp, Pratt & Whitney and BAE Systems, aredeveloping and building three variants of the F-35s for the U.S.military and 10 allies including Britain, Australia, Norway,Denmark, the Netherlands, Italy, Turkey, Israel, Japan and SouthKorea.
After Trump's Monday morning tweet, shares of NorthropGrumman were down 4.5 while shares of BAE Systems were2.4 percent lower in London.
Shares of General Dynamics, Raytheon, and UnitedTechnologies were all lower Monday, as were shares ofBoeing.
United Technologies Corp , which had a run-in with thePresident-elect over a plan to ship 2,100 jobs to Mexico fromIndiana operations of its Carrier air conditioning unit. Thecompany last week agreed with Trump to keep about 800 of thethreatened manufacturing jobs in Indiana, and retain another 300headquarters jobs, in return for state tax incentives.
The attacks on Boeing and Lockheed Martin raise concernsthat the incoming Trump administration will threaten defensecontractors' profit margins.
"His emerging habit of using Twitter as a bully pulpit couldbecome a threat to controversial high profile programs," Cowenanalysts wrote last week after Trump criticized the cost ofBoeing's Air Force One replacement program. "Even if Trump onlylaunches a bombastic Twitter shout-out, this more aggressiveapproach to contractor relations could impact the stocks."
Earlier this month, the Pentagon's chief arms buyer said hewas hopeful that Lockheed F-35 block buy will proceed.
(Reporting by Doina Chiacu and Susan Heavey; Editing by BillTrott and Nick Zieminski)