TOKYO, March 21 (Xinhua) -- Japanese Foreign Minister Taro Kono and his Russian counterpart Sergey Lavrov remained apart on Japan's plans to install a missile defense system in talks held Wednesday ahead of a bilateral leaders' summit in May.

Both countries have long-remained at odds over the sovereignty of Russia-controlled islands north of Japan's Hokkaido, but in a press briefing following the talks on Wednesday, Lavrov took aim at Japan's plans to install a new U.S.-made land-based missile defense system.

The Russian foreign minister reiterated concerns that the Aegis Ashore system "will have a direct effect on Russia's security, effectively becoming part of the U.S. missile defense network."

Kono, for his part, in keeping with Japan's stance that the system is defensive in nature and will theoretically be used to intercept ballistic missiles, asked for Russia's understanding on the matter and said the system "will not pose a threat to any neighboring country, including Russia."

The Aegis Ashore system is a land-based version of the Aegis advanced radar system and uses the same technology as those fitted to Japan's Maritime Self-Defense Force's (MSDF) Aegis destroyers.

The system consists of equipment including SPY-1 radars and a battery of Standard Missile-3s that would be deployed to intercept missiles that are flying outside of the earth's atmosphere.

Japan currently uses Patriot Advanced Capability-3 interceptors (PAC-3) surface-to-air missile defense systems, as its second line of defense, which have the capability of intercepting missiles at lower altitudes as they reenter the earth's atmosphere.

From the 5.19 trillion yen (48.83 billion U.S. dollars) allocation for defense spending, a record-high under the administration of Japanese Prime Minister Shinzo Abe, some 730 million yen (6.86 million U.S. dollars) will be used in preparation costs alone for the controversial introduction of the Aegis Ashore system.

The hefty costs were approved by Japan's Cabinet in December, with the government formally deciding to introduce two Aegis Ashore systems to cover the entire nation and for them to become operational by fiscal 2023.

Each system, developed by Lockheed Martin Corp., costs around 100 billion yen (941 million U.S. dollars), according to the Defense Ministry.

Tokyo believes that the new systems installed at stationary sites in Japan would add a new layer of missile defense along with current sea and ground-based systems.

In addition, the Defense Ministry has claimed that the new systems would help take the burden off the current MSDF Aegis-equipped destroyers, installed with Standard Missile-3 interceptors, and Japan's Air Self-Defense Force's (ASDF) ground-based PAC-3 interceptors.

Japan's Defense Ministry has voiced against installing the U.S.-made Terminal High Altitude Area Defense system (THAAD), owing to Aegis Ashore's purported cost effectiveness, among other determining factors, ministry officials said.

Russia, however, has suggested that the system might be in violation of the Intermediate-Range Nuclear Forces Treaty, a Cold War-era arms control agreement that is still in effect between Russia and Japan's ally, the United States.

It argued that the Mark-41 vertical launch system (VLS) in the Aegis Ashore system violates the treaty because of its ability to launch offensive cruise missiles, as evidenced by the system being used to launch cruise missiles on the U.S. Navy's guided missile destroyers.

Japan's increased defense spending and specifically the Lockheed Martin Corp.-developed system's introduction, alongside the U.S military's pivot to Asia, has irked Russia and other global powers concerned about regional peace and stability.

Regional security and stability aside, however, the upcoming summit between Abe and Russian President Vladimir Putin, for Japan's part, will be focused on the protracted territorial row over the Russian-administered islands, which are claimed by Japan.

To make progress on the territorial spat which has reached loggerheads, the foreign ministers discussed Wednesday potential ways both countries could cooperate economically with regards to the four islands.

Japan and Russia both claim a group of islands off Japan's northern prefecture of Hokkaido, called the Northern Territories in Japan and the Southern Kurils in Russia.

The decades-old territorial spat has prevented the two countries from signing a post-World War II peace treaty and hindered diplomatic and trade relations between the two countries.

Both parties have agreed to cooperate further in defense and other areas, including those related to search and rescue operations, medical areas, industry promotion and energy development, in line with a previously proposed plan.

Kono and Lavrov also agreed to hold a bilateral strategic dialogue in Moscow on April 19, to be attended by Japanese Vice Foreign Minister Takeo Akiba and Russian First Deputy Foreign Minister Vladimir Titov.

In a prior meeting a month earlier between Japanese and Russian economic ministers in Tokyo, Hiroshige Seko, Japan's economy, trade and industry minister, told Russian Economic Development Minister Maxim Oreshkin that the multi-faceted cooperation plan proposed by Abe in 2016 was an important foundation for future ties.

Further two-way talks between the two countries have been slated to be held in the coming months, including discussions by Japanese and Russian officials over the stalled six-party talks pertaining to the Korean Peninsula nuclear issue, sources close to the matter said.

Wednesday's meeting marks the third time since November 2016 that talks have been held between high-level officials from Japan and Russia and the first meeting Lavrov has held with a foreign minister since Putin's landslide presidential election win on Sunday.