Russia greeted visiting Japanese foreign minister Friday with a stream of defiant statements amid a flare-up of tensions caused by the long-running dispute over several Pacific islands.

Foreign Minister Sergey Lavrov began talks with his Japanese counterpart Seiji Maehara by describing as "unacceptable" the government-sponsored rally in Tokyo on Monday, when top Japanese officials demanded that Russia returns the islands it seized at the end of the World War II.

"That mars the climate in our relations and doesn't help their development," Lavrov said at a news conference after the talks. "When radical approaches take the upper hand in Japan concerning the issue of a peace treaty, it becomes pointless to conduct a dialogue on the issue."

The two countries have competing claims over four southern Kuril islands — known in Japan as the Northern Territories — and this has kept them from signing a formal peace treaty ending their World War II hostilities.

The four islands, seized by Soviet troops in the last days of World War II, give Russia a military toehold just six miles (10 kilometers) off the northeastern tip of Japan's northern Hokkaido Island. The islands are surrounded by rich fishing grounds and are believed to have offshore oil and natural gas reserves, plus gold and silver deposits.

During Monday's rally in Tokyo, Japan's Prime Minister Naoto Kan demanded the return of the islands and called the recent visit there by Russian President Dmitry Medvedev "an unforgivable outrage." Medvedev fired back Wednesday, saying that more weapons will be sent to protect the islands as an "inalienable part of Russia."

While reaffirming their nations conflicting claims to the islands, Lavrov and Maehara made some conciliatory statements Friday in an apparent attempt to ease a strain in ties.

Tensions have been building up since November, when Medvedev became the first Russian or Soviet leader to visit the islands despite strong objections from Japan. Defense Minister Anatoly Serdyukov inspected military garrisons on the islands last week and said Moscow is planning to upgrade the troops' weapons there.

Earlier this week, the state news agency ITAR-Tass cited a Defense Ministry source as saying that some of several Mistral assault ships that Russia has contracted to buy from France would be deployed in the Pacific Fleet, as part of efforts to protect the southern Kurils.

As Maehara was holding talks with Lavrov Friday, Serdyukov's aide, Gen. Yuri Yakubov, was quoted by Russsian news agencies as saying that the military plans to extend the runway on the biggest of the four islands to allow the landing of heavy Il-76 cargo planes capable of delivering hundreds of paratroopers and heavy vehicles. He also said that the military will send new helicopters and armored vehicles to the islands.

Also Friday, members of a pro-Kremlin youth group held a rally outside the Japanese Embassy in Moscow that involved flogging of an activist impersonating the Japanese premier. "We won't give up the Kurils!" the participants shouted.