Leon Panetta, the US defence secretary, has met Chinese leader-in-waiting Xi Jinping, who just days ago reappeared after a puzzling two-week disappearance.

The meeting on Wednesday was part of Panetta's weeklong trip through the Asia Pacific, in a campaign to pursue the US military's increased focus on the region.

Xi, who is tipped to succeed President Hu Jintao as leader of the Communist Party, stood to greet the US delegation in a lavish room in the Great Hall of the People and energetically shook Panetta's hand.

Once seated, he said Panetta's visit "will be very helpful in further advancing the state-to-state and military-to-military relations between our two countries".

The Chinese leader recently reappeared after not been seen since September 1. During his absence, he had cancelled meetings with dignitaries, including Hillary Clinton, the secretary of state.

Panetta told Xi that the two Pacific powers had common concerns and that he was confident they would be able to improve their dialogue.

The US defence chief also told Chinese troops on Wednesday that the US' new military focus on the Asia Pacific, including plans to put a second radar system in Japan, was not an attempt to contain or threaten China.

Delivering his message directly to the young Chinese officers and cadets at the Armored Forces Engineering
Academy, he tried to put to rest fears that the US move to add forces, ships and a missile defence system in the region is aimed at the Chinese.

Panetta laid out a more pointed argument that the growing American presence in the region includes an effort to build a stronger relationship with Beijing.

Military talks

"Our rebalance to the Asia-Pacific region is not an attempt to contain China. It is an attempt to engage China and expand its role in the Pacific ... It is about creating a new model in the relationship of two Pacific powers," Panetta said.

He acknowledged that improving relations and building trust would take time and that, "despite the distance we have traveled over the past 40 years, it is clear that this journey is not yet complete, particularly for our two militaries".

The US and China have long had a tumultuous relationship, fuelled by America's distrust of Beijing's military buildup and China's concerns about the expanded US military presence.

Tensions between the two countries have reverberated across the region, often focused on America's support of Taiwan, which China regards as a breakaway province and threatens to use force to block any Taiwanese bid for formal independence.

In recent weeks, territorial disputes between China and Japan over a string of uninhabited islands in the East China Sea have further inflamed the region.

Violent anti-Japanese protests raged across China over the disputed island called Uotsurijima in Japan and Diaoyu Dao in China.

Numerous Japanese shops, restaurants and schools were closed on Tuesday and Wednesday after they were attacked by looting protesters over the weekend.

Major manufacturers including Toyota, Canon and Panasonic also suspended part of their production in the country as a result of the protests.

Chinese officials say they want the US to remain neutral in the matter. But protesters slammed America, charging that the increased US activity in the region has emboldened Japan and other countries to challenge China in such disputes.