BEIJING - China's leader-in-waiting slammed Japan's purchase of disputed islands as a "farce", even as anti-Japan protests which had flared up in recent days subsided.
Vice-President Xi Jinping yesterday also urged the United States not to get involved and complicate matters, adopting a hardline stance in his first comments on the territorial spat.
"Japan should rein in its behaviour and stop any words and acts that undermine China's sovereignty and territorial integrity," he said in talks with visiting US Defence Secretary Leon Panetta.
It was the 59-year-old's first meeting with a foreign official since disappearing from public view for two weeks, fuelling speculation about his health and concerns if he was still in line to succeed President Hu Jintao.
Mr Xi, who quelled the rumours when he appeared in public last Saturday, looked healthy yesterday in a dark blue suit.
As Mr Panetta told reporters here after the meeting: "Frankly my impression was that he was very healthy and very engaged."
He said he also came away "very impressed" with Mr Xi, who is expected to take over leadership of the Chinese Communist Party in the coming weeks.
Mr Panetta, on his first visit to China as Pentagon chief, added in a dialogue with Chinese military cadets later that he was confident, after speaking to Japanese and Chinese leaders, that both sides could resolve their issues.
Indeed, despite Mr Xi's latest harsh tone, indications here suggest that China is putting a stop to days of angry demonstrations.
Tens of thousands had vented their unhappiness on various symbols of Japan, after Tokyo bought the Senkaku islands from a private owner on Sept 10. China refers to the rocks in the East China Sea as Diaoyu.
The protests peaked on Tuesday, the 81st anniversary of the start of Japan's invasion of north-east China. Demonstrators burned the Japanese flag, waved photos of Mao Zedong and shouted "down with little Japan". In Beijing, protesters surrounded the car of US Ambassador to China Gary Locke.
But the public display of fury pretty much vanished by yesterday, as the cities returned to normalcy. In Beijing, the major road outside the Japanese embassy was opened to traffic again. Japanese businesses also reopened, including clothing store Uniqlo and convenience chain 7-11.
But lingering fears remain.
Japanese cyclists and table tennis players have pulled out of events in China due to safety concerns, a Japanese official said.
Observers are worried the tensions may soon shift from land to sea. Japan Coast Guard officials reported 14 Chinese ships were spotted near the disputed isles.
"I wouldn't be surprised if a series of frictions and conflicts takes place near the disputed islands in the coming weeks and months," said analyst Li Mingjiang from the S. Rajaratnam School of International Studies. "But I believe armed conflict is still unlikely to happen."