Japan on Wednesday said it had begun processing applications for gas exploration in a disputed section of the East China Sea (search), a move likely to aggravate a dispute with China that has threatened Tokyo's U.N. Security Council ambitions.

Prime Minister Junichiro Koizumi (search) denied the move had anything to do with the dispute, the latest round of a long-running feud over Japan's World War II aggression.

China had no immediate comment.

Anti-Japanese protests erupted in Beijing and two other Chinese cities over the weekend, sparked by Japan's approval of a history textbook that critics say plays down Japanese military abuses such as the forced wartime prostitution of thousands of Asian women. In Beijing, protesters pummeled the Japanese embassy with rocks and bottles and attacked Japanese businesses.

Japan has demanded compensation and an official apology. Beijing has refused and on Tuesday China's premier hinted his country might exercise its veto as one of five permanent members of the U.N. Security Council to block Japan's bid for a permanent seat.

"Last century the aggression war waged by Japan inflicted huge and tremendous suffering and hardships on people in China, Asia and the world at large," Premier Wen Jiabao (search) said during an official visit to India. He said the protests should prompt "deep and profound reflections" by the Japanese.

"Only a country that respects history, takes responsibility for history and wins over the trust of peoples in Asia and the world at large can take greater responsibilities in the international community," Wen said.

China, South Korea and other Asian nations have long accused Japan of failing to express adequate contrition for its conquests of the 1930s and '40s, during which China says as many as 30 million of its people died.

The tensions also reflect Chinese unease at Japan's new political and military ambitions and competition for possible energy sources. Beijing regards Tokyo as a rival for status as the region's dominant power.

On Wednesday, North Korea, an ally of China, added its voice to criticism of the new Japanese textbooks.

"This betrays philistinism peculiar to Japan, a vulgar and shameless political dwarf," a Foreign Ministry spokesman said in a statement carried by the North's official news agency.

Eight South Korean lawmakers who were visiting Tokyo on Wednesday told Japanese Foreign Minister Nobutaka Machimura that Tokyo should "correct its attitude" and stop defending its wartime past.

They also said Japan should drop its claim to sovereignty over islets that are claimed by both South Korea and Japan in a separate dispute between the two countries.

On Wednesday Japan's trade ministry said it will allow gas drilling in waters just east of what Tokyo says is its sea border with China. Beijing disputes that border.

The ministry said in a statement it had instructed officials to process the applications "as quickly as possible." An agency official said approval was expected within two to three months.

Japan has repeatedly protested Chinese exploration of the fields, saying the activities extend into Tokyo's exclusive economic zone. But Beijing says its surveys are within its zone and has refused to halt them or share the results.

Japan's government is campaigning for a permanent Security Council seat in recognition of its status as the world's second-biggest economy, after the United States.

The United States, Russia, Britain, France and China each hold a permanent place on the Security Council. For Japan to get one, the U.N. Charter would have to be amended, which would require approval by the Security Council, so China could use its veto to block any change.

Washington, meanwhile, accused China of failing in its responsibility to protect the Japanese Embassy in Beijing from the protesters.

"China does have a responsibility to prevent violence against foreign missions in Beijing," State Department spokesman Richard Boucher said Tuesday. "We think that it's very regrettable that this one did turn violent and was not under control."