The central government has deleted sentences on promoting economic cooperation with Russia in one of Japan's key documents in yet another show of staunch opposition to Moscow's invasion of Ukraine.

In updating its document on Japan's strategy to expand infrastructure exports Friday, the government completely removed sentences regarding an eight-point plan for economic cooperation with Russia, which was proposed in May 2016 by then-Prime Minister Shinzo Abe when he held talks with Russian President Vladimir Putin.

Under the plan, Japan had intended to break the deadlock over a long-standing territorial dispute with Russia over a group of islets off Hokkaido.

The islets are called the Northern Territories in Japan and the Southern Kurils in Russia. The issue has prevented them from signing a post-World War II peace treaty.

Even before the deletion, economic cooperation with Russia was already frozen in the wake of its February invasion of Ukraine, according to the Ministry of Economy, Trade and Industry.

The eight areas of cooperation included projects related to airports and seaports in the Russian Far East, oil and gas development, health care, tourism and academic exchanges.

In March, Chief Cabinet Secretary Hirokazu Matsuno told a news conference that Russia's aggression in Ukraine had made it difficult to deepen economic cooperation with Moscow.

Japan has joined Western nations in imposing a spate of severe economic sanctions against Russia, such as freezing the assets of Putin and the Russian central bank, as well as excluding some major lenders from a key international payment network.