Dmitry Medvedev 'planning new visit to disputed Kurils'
Russian President Dmitry Medvedev is said to be planning to visit more of the disputed Kuril Islands, despite growing anger from Japan.
He became the first Russian leader to visit one of the four islands on Monday, prompting Tokyo to temporarily recall its Moscow ambassador.
Foreign Minister Sergei Lavrov has said that Mr Medvedev would now make another trip aimed at securing investment.
The Kuril Islands were seized by Soviet troops at the end of World War II.
Hours after Japan announced it was recalling its ambassador, Mr Lavrov told reporters in Norway that Tokyo's "strong reaction" was unacceptable.
He denied that Russia had done anything to harm diplomatic ties.
"I don't think we plan any steps on our side because we never undertook anything that would worsen our relations with Japan," he said.
Japanese Foreign Minister Seiji Maehara said earlier on Tuesday that he wanted more details from the ambassador about the four-hour trip during which Mr Medvedev chatted with residents and visited a fish-processing factory.
The minister warned that the visit would "hurt the feelings of the Japanese people" - and by recalling its ambassador to Moscow, Tokyo has acted to show its displeasure, says the BBC's Roland Buerk in Tokyo.
A senior Russian MP warned that it could take at least six months before political relations could resume.
"Neither Russia nor Japan would actually go to war. Nonetheless, the intensity of our political relations will of course decrease very seriously," said Gennady Gudkov, deputy chairman of the Duma's security committee.
President Medvedev is due to meet Japan's Prime Minister Naoto Kan on the sidelines of an Asia Pacific summit set for 13-14 November in Japan.
"I believe the bilateral meeting will be held," Japanese chief spokesman Yoshito Sengoku said.
Japanese Economic Minister Banri Kaieda told reporters he was concerned about the possible economic repercussions of the row with Russia.
"Japan and Russia have deep ties when it comes to energy and natural resources development," Mr Kaieda said.
"I am worried about the impact on economic relations from the Russian president's visit to the Northern Territories," he said, using the Japanese name for what Russia calls the Southern Kuriles.
The dispute has strained relations between Tokyo and Moscow ever since World War II, preventing the signing of a formal peace treaty.
Before Russia took control of the islands, about 17,000 Japanese residents lived in the Kurils.
The islands have rich fishing grounds, mineral deposits and possibly oil and gas reserves.
Mr Medvedev's visit comes as Japan is locked in a separate territorial dispute with another powerful neighbour.
Ties between China and Japan have been strained by a row over islands in the East China Sea - known as Senkaku in Japan and Diaoyu in China - that both claim.