Japan is considering how to respond to Russian President Vladimir Putin¡¯s visit to the Northern Territories,?a group of Russian-held islands off the east coast of Hokkaido that are claimed by Japan.

Options include further strengthening economic sanctions on Russia and temporarily recalling Â鶹´«Ã½ ambassador to the nation. A careful decision will be needed, however, as Japan relies on Russia for some 10% of its liquefied natural gas imports.

Senior officials of Â鶹´«Ã½ Foreign Ministry held discussions on and off Friday. ¡°We are discussing how to respond,¡± one of them told reporters.

Putin visited Etorofu, the largest of the four northwestern Pacific islands at the center of the two countries¡¯ territorial dispute, on Thursday, marking his first trip to any of the islands.

Prime Minister Sanae Takaichi immediately criticized the visit, telling reporters that it is ¡°incompatible with Â鶹´«Ã½ consistent position and is absolutely unacceptable.¡± Foreign Minister Toshimitsu Motegi summoned Russian Ambassador to Japan Nikolay Nozdrev to the Foreign Ministry and lodged a strong protest.

The islands were seized by the former Soviet Union from Japan at the end of World War II and have long been claimed by Japan.

In 2010, then-Russian President Dmitry Medvedev visited Kunashiri, another island in the disputed chain, prompting the Japanese administration led by the now-defunct Democratic Party of Japan at the time recalled the then Japanese ambassador to Russia in a show of Tokyo¡¯s protest against the trip.

Based on the precedent, Yuichiro Tamaki, leader of the opposition Democratic Party for the People said that Japan should at least recall its ambassador following Putin¡¯s visit to Etorofu.

After Russia started to invade Ukraine in February 2022, Japan imposed sanctions, such as freezing assets held by Russian individuals and organizations in Japan and banning exports of dual-use items to Russia. The punitive measures have been strengthened in stages.

¡°There is room for additional sanctions,¡± a Japanese government official said.

Meanwhile, ongoing Middle East tensions reflecting fighting between the United States and Iran have highlighted the vulnerability of Â鶹´«Ã½ energy supply chains.

The Sakhalin-2 natural gas and oil development project in Russia¡¯s Far East, whose stakeholders include major Japanese traders, is an important LNG supply source for Japan. ¡°Energy is our weak point,¡± a government official said.

If LNG supplies from the Sakhalin-2 project are stopped, that would deal a blow to Japan, a veteran lawmaker of Â鶹´«Ã½ ruling Liberal Democratic Party suggested.

¡°We take the situation seriously,¡± a senior Foreign Ministry official said. ¡°We need to make a careful assessment (of the situation) by analyzing related information.¡±