President Vladimir Putin visits China Tuesday on the first Asia trip of his new Kremlin mandate aiming to tighten an increasingly close alliance that is key for Russia's diplomatic and economic strategy.

Putin, who began a third term as president less than a month ago, has already made a lightning trip to Germany and France but will symbolically be visiting Beijing before the United States.

The sometimes troubled Moscow-Beijing relationship has warmed during Putin's 12 years of domination over Russia and the two governments are notably in lockstep in opposing outside intervention to solve the Syrian crisis.

"One can understand where the vector of Russian policy is turned" with the Beijing visit, commented Georgy Kunadze, a China expert at the Russian Academy of Sciences and a former diplomat.

Putin is likely to coordinate positions with President Hu Jintao on the violence in Syria and the Iranian nuclear crisis, with the West keenly aware both UN Security Council permanent members are prepared to wield their vetoes.

With Moscow set to host a third round of delicate talks on the Iranian standoff on June 18 and 19, Putin will also hold a closely-watched meeting in Beijing with Iranian President Mahmoud Ahmadinejad, who will be attend a regional summit.

But economic issues are also set to figure prominently on the three-day trip, particularly the energy sector, as Russia searches for new markets while China seeks cheap natural resources.

Russian energy giant Gazprom over the last week held talks in China in an apparent bid to overcome continued disagreements over gas prices in a landmark contract that has been in its final stages since last summer.

The long-term deal envisages that Russia is to annually supply nearly 70 billion cubic metres of natural gas to China over the next 30 years, under a framework agreement signed in late 2009.

Russian Deputy Prime Minister Arkady Dvorkovich said this week that the sides have still not reached an agreement on price, and it is unlikely that a final deal will be signed during Putin's visit.

Meanwhile, Russian media reported this week that the two countries are also preparing to launch a joint aerospace project to develop a long-range passenger plane based on Russian know-how and Chinese investment that would challenge giants Airbus and Boeing.

The presidency of Dmitry Medvedev -- who held the Kremlin from 2008 to May of this year while Putin served as prime minister -- was marked by optimism about Russia's strengthening relations with the United States.

But Putin led observers to believe his foreign policy will be rooted elsewhere when he surprisingly cancelled a trip to the United States last month that was to have been the first foreign visit of his new term.

On Wednesday, Putin will participate in a Beijing summit of the Shanghai Cooperation Organisation, a security body that includes Russia's former Soviet partners in Central Asia and a handful of observer states, including Iran.

Putin's attendance at the SCO summit -- seen as a fledgling eastern counterpart to NATO -- is also symbolic given that he was absent from the NATO summit in Chicago amid a row with the United States over missile defence.

The Russian leader's meeting with Ahmadinejad is expected to come on the sidelines of the SCO meeting, with his foreign policy aide saying the talks would let "Putin personally feel the tension around the Iranian issue and how it is perceived in Tehran."

Putin is a frequent guest of Chinese leaders, last visiting Beijing as recently as October in his capacity as prime minister. It was his only foreign trip after he announced in September his plan to run for president.

A month after his visit, he was awarded China's version of the Nobel prize for "keeping world peace".

Relations between the territorial giants, who share a border of 4,000 kilometres (2,500 miles), have improved since Putin first entered the Kremlin in 2000, especially after outstanding border issues were regulated in 2005.

While Russia's economy pales in comparison with China's growing economic might, Putin indicated in his pre-election foreign policy manifesto that Moscow does not view its neighbour to the east as a threat.

"Growth of China's economy is not a threat," he wrote, instead seeking "Chinese potential in developing Siberia and the Far East," regions with a wealth of energy resources that are battling a population drain.

Putin will be arriving in China from ex-Soviet Uzbekistan, where he is due on Monday to meet President Islam Karimov.