Photo/IllutrationJapan's Defence Minister Takeshi Iwaya, second right, shakes hands with Russia's Defence Minister Sergei Shoigu, left, while Japan's Foreign Minister Taro Kono, right, and Russia's Foreign Minister Sergei Lavrov, second left, look on after their 2+2 joint press conference at the Iikura Guest House in Tokyo, May 30, 2019. (Pool Photo via AP)

Russia and Japan accused each other of military buildups as their foreign and defense ministers met in Tokyo on Thursday for talks that failed to make progress on decades-long island disputes.

Russian Foreign Minister Sergey Lavrov said at a joint news conference after the talks that Russia was concerned about Tokyo's plan to build a pair of land-based Aegis Ashore missile defense systems, saying they pose a "potential threat to Russia."

The Aegis Ashore systems, planned for deployment in Akita on Japan's northern coast and in Yamaguchi in the southwest, are part of Japan's rapidly expanding missile defense system to bolster its ability to counter potential threats from North Korea and China. Under guidelines approved in December, Prime Minister Shinzo Abe's government plans to increase purchases of expensive American military equipment including F-35 stealth fighter jets and cruise missiles as Japan continues to expand its military cooperation with the U.S.

Japanese Foreign Minister Taro Kono accused Russia of a military buildup on Russian-controlled islands claimed by both countries.

The dispute over the islands, which Russia calls the southern Kurils and Japan the Northern Territories, has prevented the two countries from signing a peace treaty formally ending their World War II hostilities.

"Our country's legal position does not accept the missile drills, fighter aircraft deployment, and enhancement of the military presence in the Northern Territories," Kono said.

Japanese Defense Minister Takeshi Iwaya told his counterpart, Sergei Shoigu, and Lavrov that the Aegis Ashore interceptors are "purely for defensive purposes and never for use to threaten Russia or other countries."

Lavrov brushed off Kono's criticism, saying his country is only operating in its own territory. "Under international law, the territory is under Russia's sovereignty and those are Russian military activities in Russian-held territory," he said.

Regaining the disputed islands, which are north of Japan's northern main island of Hokkaido, has been a priority for Abe and his conservative base. Abe is eager to make progress on the dispute with Russia and find opportunities to cooperate in developing oil and gas and other natural resources.

In November, Abe and Russian President Vladimir Putin agreed to accelerate negotiations based on a 1956 Soviet proposal to return two of the islands to Japan, but progress has since stalled.