The Pentagon is providing Japan with initial pricing and technical data to decide if it wants to buy a ground-based version of the Aegis missile defense system used on U.S. Navy cruisers and destroyers, according to officials and documents. Exchanges of information about the Aegis Ashore system, with radar and command-and-control equipment from Lockheed Martin Corp. and a missile from Raytheon Corp., is the first step in a process that sometimes takes years to complete, according to the officials, who asked not to be identified discussing the preliminary contacts. It could culminate in a formal notification to the U.S. Congress of a proposed sale. In a visit to Tokyo on Monday, President Donald Trump talked up Japanese purchases of U.S. defensive military systems, both to blunt the threat from North Korea’s nuclear program and to improve the balance of trade between the two allies. “One of the things I think is very important is the prime minister is going to be purchasing massive amounts of military equipment, as he should,” Trump said with Prime Minister Shinzo Abe by his side. “It’s a lot of jobs for us and a lot of safety for Japan.” Japanese officials have expressed interest in buying two Aegis Ashore systems that would go into operation by 2023, according to media reports in Japan. A Japanese official with the country’s acquisition agency said the government is working to introduce new ballistic-missile defenses, based around Aegis Ashore, as quickly as possible. Relevant departments within the Japanese military are coordinating to speed consideration, but at this stage it hasn’t been decided which version would be acquired or exactly when they’d be introduced, according to the official, who spoke on condition of anonymity to discuss internal deliberations. Ellen Lord, the Pentagon’s top weapons buyer, was briefed by staff about the status of the talks before a meeting Monday with Lockheed officials including Chief Executive Officer Marillyn Hewson. Aegis Ashore is a deckhouse that replicates the Aegis air and missile defense system on Navy vessels. A version has been operational in Romania since 2016. A second site will be built in Poland for operations starting next year. Advanced Versions Japan is receiving information about the existing system as well as one with an advanced radar that Raytheon is developing for the newest Navy destroyers and another with a solid-state radar from Lockheed that hasn’t been purchased by the U.S., according to the officials and documents. Costs for the different versions haven’t been disclosed. The U.S. Navy’s international affairs office plans to provide Japan with packages of information this month on the newer versions. Japan already operates four Kongo-class destroyers equipped with Aegis missile defense equipment. Lockheed spokeswoman Maureen Schumann and Raytheon spokesman Mike Doble declined to comment. Tom Crosson, a spokesman for the Pentagon’s Defense Security Cooperation Agency, which is managing the information exchange on behalf of the State Department, said in an email that “as a matter of policy, we do not comment or confirm proposed defense sales or transfers until they have been formally notified to Congress.” The increased activity concerning Japan’s potential purchase of the Aegis Ashore system comes as Trump is seeking $4 billion in added U.S. spending “to support urgent missile defeat and defense enhancements to counter” the threat from North Korea’s missiles. The amendment to this year’s defense budget proposed by Trump on Monday would include funds for a new missile-defense field at Fort Greely, Alaska; initial funding for 20 more ground-based interceptors made by Orbital ATK Inc. and Raytheon to be deployed there; 16 newer model Standard Missile-3 interceptors from Raytheon for Navy ships; and 50 additional Thaad interceptors made by Lockheed.