Russia complained Tuesday about Japan's plan to deploy U.S.-developed missile defense systems, but the foreign and defense ministers of the two countries agreed to work together toward the denuclearization of North Korea and step up security cooperation.

In response to Russia's deep-seated concern about the deployment, Japanese Defense Minister Itsunori Onodera said it is "purely for national defense."

(Japanese FM Taro Kono, 2nd from right, and Russian FM Sergei Lavrov, 2nd from left)

The friction over the installation of two land-based Aegis Ashore stations, which Japan sees as necessary to protect its territory from North Korean ballistic missile strikes, re-emerged as Onodera and Japanese Foreign Minister Taro Kono met their Russian counterparts Sergei Shoigu and Sergei Lavrov in Moscow.

Russia regards the two missile defense stations, possibly to be deployed around 2025 in Japan's northern and southwestern regions, as an addition to the U.S. missile shield in the Asia-Pacific region.

Speaking to reporters after the "two-plus-two" meeting, Onodera also said he has called on Russia to show restraint in building up military forces on isles off Japan's northernmost main island of Hokkaido.

The meeting, the first since March last year, came amid an ongoing detente on the Korean Peninsula after the historic U.S.-North Korea summit in June, with no missiles launched by Pyongyang this year, in contrast to 2017 when it repeatedly test-fired ballistic missiles and conducted its sixth and most powerful nuclear test to date.

Tokyo is hopeful that cooperation with Moscow on North Korea and the strengthening of the security dialogue will also help resolve a decades-old territorial spat over the disputed islets.

(A U.S. Aegis Ashore missile defense complex)
[File photo]

The four ministers consented to holding an annual security conference involving the two countries' foreign and defense officials at vice-ministerial level, and to arranging for a port call to be made by naval vessels of the Russian Pacific Fleet at Hakodate in Hokkaido in October.

They also agreed to realize a visit by a Japanese fact-finding mission on Aug. 16-20 to the islands controlled by Moscow but claimed by Tokyo, in a bid to work toward joint development of the disputed isles.

Kono, apparently with the territorial issue in mind, stressed the importance of mutual communication to solve bilateral problems at a press conference after the meeting, saying he wants to "develop relations between Japan and Russia in every field."

In their one-on-one session, Kono and Lavrov concurred that Japanese Prime Minister Shinzo Abe and Russian President Vladimir Putin will meet in Vladivostok and that the two foreign ministers will meet again in New York, both in September.

Kono told reporters he did not discuss whether North Korean leader Kim Jong Un will take part in an annual economic forum to be held next month in the Russian Far East city.

Abe has said he is seeking a summit with the North Korean leader but will not consider economic cooperation or normalization of ties without a resolution to the issue of Japanese abducted by Pyongyang in the 1970s and 1980s.

During the latest meeting, Japan again sought cooperation from Russia in settling the abduction issue at an early date, officials said.

Japan and Russia held their first two-plus-two talks in November 2013 and second in March 2017, both in Tokyo. The hiatus of over three years was due to Moscow's annexation of the Crimean region of Ukraine in March 2014.

Onodera's visit to Moscow marked the first time a Japanese defense chief has visited Russia since January 2006.

(Kunashiri Island seen in distance from Hokkaido, Japan)

The third round was set when Abe and Putin met in Moscow in May, when they agreed to make renewed efforts to sign a postwar peace treaty and accelerate bilateral economic cooperation.

One of the obstacles to signing a peace treaty is the dispute over the contested islands of Etorofu, Kunashiri, Shikotan and the Habomai group off Hokkaido.

The islands called the Northern Territories in Japan and the Southern Kurils in Russia were seized by the former Soviet Union after Japan's surrender in World War II in August 1945.

The following is the gist of the outcome of "two-plus-two" security talks and one-on-one meetings between foreign and defense ministers of Japan and Russia held Tuesday in Moscow.

-- Russia expresses concerns about Japan's plan to introduce two land-based Aegis Ashore missile defense systems.

-- Japan demands Russia show restraint on conducting military exercises on disputed islands off Hokkaido.

-- Japan and Russia agree to closely cooperate to realize denuclearization of North Korea.

-- Japan seeks cooperation from Russia in settling the abduction issue at an early date.

-- Japan and Russia agree to step up security cooperation.

-- Japan and Russia agree to realize a visit by a Japanese fact-finding mission on Aug. 16-20 to the islands controlled by Moscow but claimed by Tokyo.