Beijing on Monday urged Tokyo not to engage in empty talk about "dialogue" and to stop infringing on China's territorial sovereignty, after the Japanese prime minister accused China of setting "certain conditions" for a summit between the two sides.

The Japanese government and right-wing forces have been beefing up their rhetoric and actions around the Diaoyu Islands issue.

Observers said right-wing forces in Japan were flaring up the dispute to push politicians to a more conservative stance before the country's upper house election, which is scheduled for July 21.

The Abe administration also wants to woo voters by bowing to right-wing pressure on the islands issue while showing its diplomatic capability with overtures toward communication, observers said.

The current difficult situation between China and Japan was caused by Japan's successive provocations over the Diaoyu Islands, Chinese Foreign Ministry spokeswoman Hua Chunying said at a daily news conference on Monday.

She made the remarks a day after Abe said he wanted talks with Chinese leaders but would not accept any so-called conditions set by China for such meetings.

"China has been committed to properly controlling and settling the Diaoyu Islands issue through dialogue," Hua said. "Japan should not solely resort to empty talk about 'dialogues' but needs to face up to history and reality."

Yang Bojiang, an expert on Japanese studies at the Chinese Academy of Social Sciences, said the major obstacle for a bilateral summit meeting is not from Beijing, but from Tokyo.

"Abe would never make any compromise before the election," Yang said. "What he wants is to avoid escalating tension while attracting international attention by making the gesture."

On Monday, four fishing boats carrying members of a Japanese right-wing political group and Kenji Yamada, a parliamentarian and member of the ruling Liberal Democratic Party, sailed in waters near the Diaoyu Islands while four Chinese vessels patrolled nearby.

It was the 15th trip by the group to the islands since May. They left Ishigaki, Okinawa Prefecture, for the islands on Sunday evening.

On the same day, the Chinese marine surveillance ships Haijian 51, Haijian 23, Haijian 49 and Haijian 5001 conducted their regular patrols in waters surrounding the islands, according to China's State Oceanic Administration.

During the patrol, the Chinese fleet spotted and monitored Japanese vessels illegally sailing in the area. They collected evidence of the Japanese ships and took law enforcement measures, the administration said.

Without any confrontation, the Japanese boats, with more than 30 people on board, had left the area by Monday afternoon, an official from the nationalist Channel Sakura satellite broadcaster told AFP.

Xinhua and AFP contributed to this story.