Putin will be accompanied by a 160-member delegation for his two-day visit -- his first abroad since he declared a planned Kremlin comeback -- during which he will meet his Chinese counterpart Wen Jiabao and President Hu Jintao.

China's foreign ministry said Tuesday the two countries had already signed 16 economic and trade agreements worth more than $7 billion "in the fields of technology transfer, research and development and mineral development".

It gave no further details of the deals, which were signed at a summit Monday held ahead of Putin's visit.

Observers say the Russian prime minister may lay out his foreign policy priorities for years to come during the trip, which follows last month's announcement that he plans to reclaim the presidency.

Putin has paid frequent visits to China -- where he is very well known -- in his capacities as president and then prime minister since he took power in 1999.

Plans to pump Russian gas to China are expected to top talks between the two sides. Russia is the world's largest energy producer and China the largest energy consumer.

Russian gas giant Gazprom and China National Petroleum Company signed a framework agreement in 2009 that could eventually see almost 70 billion cubic metres of Russian gas sent to China annually for the next 30 years.

However, talks have become bogged down in pricing disagreements. Hu's visit to Moscow in June delivered no breakthrough, and Chinese state media said this trip was also unlikely to yield a firm, final contract.

China's foreign ministry spokesman Liu Weimin said Monday that "new progress and achievements" had been made in energy talks, but did not specify whether he was referring to the gas agreement.

The Stockholm-based International Peace Research Institute says that China's dependence on Russia for arms and energy imports has declined and Moscow's position when dealing with Beijing has weakened as a result.

It pointed out in a report last week that China had found other partners in the oil and gas sectors in the Middle East, Africa or central Asia.

Russia and China set much store by their bilateral ties and are often viewed as partners in international diplomacy.

China became Russia's top trading partner for the first time last year and the two countries want to nearly double trade to $100 billion by 2015 and then to $200 billion by 2020.

Both countries are veto-wielding permanent members of the UN Security Council, and last week infuriated the West by blocking a UN resolution against Syrian President Bashar al-Assad's deadly crackdown on protests.

On Monday, Russian Foreign Minister Sergei Lavrov said Moscow and Beijing were ready to propose a new UN resolution on Syria that would condemn violence carried out both by al-Assad's regime and the rebel opposition.

But some experts say that in reality there is little trust between the two countries.

Russia's security service the FSB revealed last week that it had been holding a Chinese national identified as Tong Shengyong for the past year on espionage charges linked to Russia's S-300 surface-to-air missiles.

Neither the Kremlin nor Beijing, a major purchaser of Russian weapons, have issued any comment, in a possible attempt to suppress the issue ahead of Putin's visit.