China's troubled Xinjiang region shares borders with eight countries, which is perhaps one reason President Hu Jintao dropped out of the G8 summit to head home, underscoring the seriousness of the situation and the need to quickly bring the vast oil-rich region under control.

Xinjiang touches Russia, Pakistan, Afghanistan, India, Mongolia, Kazakhstan, Kyrgyzstan, Tajikistan, besides the Tibet Autonomous Region.

China, as this piece for the Council on Foreign Relations points out, has long been concerned that these states on its periphery both in central and south Asia may be tempted to back a separatist movement in Xinjiang because of the Uighurs' cultural ties to its neighbours.

To that extent it has cultivated close ties with some of these neighbours, even trying to promote direct trade between Xinjiang and the provinces of neighbouring countries just over the border.

In April this year, the Xinjiang Uygur autonomous region signed an agreement to establish friendly provincial relations with Pakistan's North West Frontier Province, according to this report in the state-run China Daily.

The two sides agreed to explore partnership in oil and gas resources, bilateral trade and agriculture besides vowing to accelerate work on a long-planned direct rail link.

More importantly, Pakistan's ambassador to China, Masood Khan, who signed the agreement, said the two sides must deepen their partnership to oppose "terrorism, extremism and separatism."

Beijing's concerns over the instability in Pakistan especially in the NWFP spilling over into Xinjiang have frequently surfaced, although in perhaps characteristic style, they have gone about it in low-key manner, quite different from the Western approach.

In March this year, Xinjiang governor Nuer Baikeli, speaking on the margins of China's annual parliament meeting said his region faced threats from violence rippling across south and central Asia. Militant attacks in Pakistan and even the one in Mumbai and the violence in Afghanistan showed Xinjiang had reason to fear, he said.

The links go back to the Soviet occupation of Afghanistan. As the piece for the Council of Foreign Relations noted, many Uighurs travelled into Pakistan and Afghanistan in the 1980s and 90s, where they were exposed to Islamic extremism.

China has worried ever since about the militants slipping in and out Xinjiang.

Pakistan's Daily Times noted the Chinese concerns, but said Islamabad could only play a limited role given that it was itself fighting to regain control of its territory in the northwest from the militants.

[PHOTO: A boy runs past an overturned car just outside the Uighurs neighbourhood in Urumqi in China's Xinjiang Autonomous Region July 8, 2009. REUTERS/Nir Elias]

While Indian Prime Minister Manmohan Singh's meeting with Pakistani President Asif Ali Zardari in Russia captured all the attention,  Singh's talks with Chinese President Hu Jintao may turn out to be just as important in easing off renewed pressure on the complex relationship between the world's rising powers.

India said this month it will bolster its defences on the unsettled China border, deploying up to 50,000 troops and its most latest Su-30 fighter aircraft at a base in the northeast.

While upgrading the defences has been a long-running objective, the timing seemed to suggest New Delhi's renewed fears of "strategic encirclement" by China by deepening ties with all of its neighbours, not just Pakistan but also Sri Lanka and Nepal.

The chief of the Indian air force, reflecting the anxieties in the security establishment, said China was a far bigger threat than Pakistan because so little was known about Beijing's combat capabilities.

Predictably enough, the Indian military moves and statements drew a strong response from China's official media warning that New Delhi's tough new posture was dangerous if it thought it would compel China to cave in. Beijing was in a different league, both in terms of national power, economic scale and global influence, the media said.

On Monday, Hu and Singh met on the sidelines of the Shanghai Cooperation Organisation and the BRIC meeting that followed in the Urals city of Yekaterinburg. Details from the meeting were sketchy, but the Press Trust of India said the two leaders supported an early meeting of a joint economic group to push trade ties. 

They also touched on the border dispute at the heart of the more than four decades of distrust, noting that top negotiators were due to meet in August. The People's Daily said Hu stressed on expanding economic cooperation and investment flows and aims to take bilateral trade to $60 billion in 2010. It stood at $51.8 billion in 2008, the paper said.

India's decision to attend the SCO, where it has observer status, was also a step forward. Since its inception the forum has been seen in India as China-centric with the main strategic objective of limiting U.S. dominance on China's periphery and in that way prevent the hemming-in of both China and Russia.

By attending the summit is New Dehi signalling its intention to engage China on a broad front and not shy away?

And did Beijing shift ground a bit by acceding to the declaration by the BRIC - Brazil, Russia, India and China - calling for U.N. reform and saying that the grouping understood and supported India and Brazil's aspirations to play a greater role in the United Nations.

Both Brazil and India are candidates for permanent members of the Security Council and Beijing has long been cold to the idea of at least its southern neighbour getting a place on the high table. It wasn't a ringing endorsement at Yekaterinburg but perhaps the first shuffling of chairs?

[Manmohan Singh and Hu Jintao at the SCO summit and a Chinese soldier at the border]