A Lockheed Martin Corp. executive said Tuesday its SPY-7 radar is "fully capable" of being installed on Japan's new naval vessels, expressing confidence that there is no alternative, despite calls for a review of the current plan after the country scrapped a land-based Aegis missile defense system earlier this year.

"We are 100 percent confident," Tom Rowden, vice president responsible for the U.S. company's overseas strategy and business development, said in an online interview with Kyodo News, should Japan formally decide to stick with the plan for the vessels, stressing that the company has been providing radar systems to the country for over 30 years.

Photo taken March 19, 2020, from a Kyodo News helicopter shows the Japanese Maritime Self-Defense Force's seventh Aegis-equipped destroyer, Maya, which was put into commission after it was handed over to the Defense Ministry at a shipyard in Yokohama, near Tokyo, the same day. (Kyodo) ==Kyodo

His remarks came after some lawmakers of Japan's major ruling party called for a review of the plan, as the Defense Ministry is considering building two Aegis-equipped ships while examining three sea-based options in place of the land-based system aimed at intercepting missiles from North Korea.

Citing safety and technical reasons, the Japanese government decided in June to give up on deploying the U.S.-developed Aegis Ashore land-based system. But it plans to maintain the adoption of SPY-7 to avoid cancellation fees.

In 2018, the Japanese ministry selected Lockheed Martin's Aegis radar after determining that it is superior to another supplied by Raytheon Technologies Corp.

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However, given that the course is now set for the sea-based options, some lawmakers of the ruling Liberal Democratic Party have raised concern that interoperability between Japan's Maritime Self-Defense Force and the U.S. Navy may be undermined as the latter decided in 2013 to use SPY-6, another Aegis radar supplied by Raytheon Technologies.

A group of LDP lawmakers said in a proposal handed to Defense Minister Nobuo Kishi in October that Japan will have to pay the development and repair costs on its own for SPY-7, whereas if the country uses SPY-6, it will be able to utilize the U.S. Navy's know-how.

But Rowden said, "The beauty of SPY-7 is that it operates with the Aegis combat system," which is developed by Lockheed Martin.

"As a result of that, the interoperability, which is dependent upon the combat system is fully guaranteed," he said, adding the radar's other advantages include its greater detection range and ability to function even during maintenance.

In a recent interview with Kyodo News, Scott Spence, a director at a Raytheon Technologies unit, said that Japan could reconsider the radar selection.

"I think things may have changed over the last couple of years and folks may need to reconsider things based on the world situation and the threats that have changed since previous decisions were made," Spence said.

File photo taken on the Hawaiian island of Kauai in January 2019, shows an Aegis Ashore missile-defense system at the Pacific Missile Range Facility of the U.S. Navy. (Kyodo)

"Having a common set of hardware and capabilities between the navies is really important to the collaboration," he said. "It provides that level of training and maintenance and tactics that those naval officers can share."

Regarding the Aegis ships, Japan is seeking to establish a comprehensive air and missile defense capability, designed to protect not only against ballistic missiles, the main purpose of the scrapped land-based system, but to counter cruise missiles and fighter jets.

Spence emphasized that the SPY-6 radar, developed specifically for the U.S. Navy, can simultaneously detect several threats, such as fighters, cruise missiles and incoming ballistic missiles.

He claimed the rival company's radar is a derivative of a ballistic missile defense system, which is now in Alaska but still not in operation.

Rowden, however, rejected his assertion, saying SPY-7 will be better at detecting several different types of threats at the same time, not just ballistic missiles.

He added the radar's installation on five Spanish and 15 Canadian warships will lead to an expansion of the supply chain and help lower costs.