Japan is considering downsizing two destroyers to be built with the Aegis ballistic missile interceptor system from their original design in a bid to increase their mobility, government sources said Tuesday.

While the destroyers were principally designed to protect against ballistic missiles, the government also plans to make them multipurpose vessels capable of carrying the U.S.-developed Tomahawk cruise missile, which it is considering introducing, according to the sources.

Photo taken March 19, 2021, from a Kyodo News helicopter shows the Haguro Aegis-equipped destroyer of the Japanese Maritime Self-Defense Force in Tokyo Bay off Yokohama. (Kyodo) ==Kyodo

The government originally planned to build destroyers with a standard displacement of about 20,000 tons, almost the same as the Maritime Self-Defense Force's largest ship, the carrier Izumo. But now they will be scaled down to nearly on par with the 8,200-ton Maya, the nation's biggest Aegis-equipped vessel, the sources said.

After internal discussions, the MSDF has concluded that the new destroyers can be downsized while maintaining the necessary air defense capabilities, according to the sources.

Through the remodeling, the government aims to improve the two ships' interoperability with other MSDF vessels, including the existing eight MSDF Aegis destroyers, and enable their swift deployment to waters such as those off Okinawa, where tensions have grown over the Taiwan Strait, the sources said.

To deal with North Korea, which has a robust ballistic missile program, Japan initially intended to build large destroyers to add stability to their hulls while they remain on alert for an extended period for possible ballistic missile launches.

But it was feared the size would slow them down and make it difficult for them to work seamlessly with other MSDF ships.

Japan decided in 2020 to build the two Aegis destroyers as an offshore alternative to the U.S.-developed Aegis Ashore missile defense systems it had planned to deploy in northeastern and western Japan. The plan to build the land-based systems was ditched following technical problems, ballooning costs and public opposition.

The government aims to commission one of the destroyers at the end of the fiscal year through March 2028 and the other at the end of the subsequent fiscal year, according to the sources.

The plan to purchase U.S.-made sea-launched Tomahawks, which have a range of up to 2,500 kilometers and can travel at a relatively low altitude, has emerged as Japan aims to articulate plans to acquire a "counterstrike capability" in its key long-term diplomatic and security policy guidelines to be updated by the end of this year.

In its budget request for the new fiscal year from April, the Defense Ministry has requested funding for designing new Aegis destroyers and procuring their engines without specifying their amount.

The ministry also aims to use Lockheed Martin Corp.'s SPY-7 radar, which was supposed to be used for the land-based Aegis Ashore system, on the new destroyers while adding the ability for them to respond to hypersonic glide weapons, the sources said.

Hypersonic glide weapons travel at many times the speed of sound and are thought to be difficult to intercept with existing anti-missile systems. They are being developed by countries such as China and Russia.