Russia and China on Monday pledged to ramp up efforts to promote a just world order as they signed dozens of deals ranging from energy to finance.

Visiting Chinese Prime Minister Li Keqiang and his Russian counterpart Dmitry Medvedev oversaw the signing of 38 agreements, including a deal to open a yuan-ruble swap line worth 150 billion yuan ($24.5 billion) in an apparent bid to reduce dependence on the US dollar.

Li's first visit to Russia as prime minister comes at a sensitive time, with the Kremlin locked in a battle of wills with Washington and Brussels over Ukraine.

Accused by Kiev and the West of stoking a bloody insurgency in eastern Ukraine, Russia is facing its most serious isolation since the end of the Cold War, with its economy shaken by several rounds of Western sanctions.

Russia hopes intensified cooperation with Asia will help it ride out EU and US sanctions.

After talks with Li in Moscow, Medvedev said the two countries should think many moves ahead.

"My colleague Mr Prime Minister just recently noticed that our peoples like to play checkers and chess. And those who think strategically play checkers and chess well," Medvedev told reporters after the talks.

"And also those who think about the future play well, that is why we should think about the future, developing our relations for years to come."

Li, who is set to meet President Vladimir Putin on Tuesday, also resorted to allegory, saying Russia's famous nesting doll symbolised huge joint opportunities.

"I believe that the matryoshka symbolises the vast potential for cooperation between China and Russia," he said in comments translated into Russian.

"Both countries are full of determination to develop eternal friendship and together defend peace and stability in the region and the world on the whole."

The two countries agreed to jointly celebrate the 70th anniversary of the defeat of Nazi Germany in World War II next year, a hugely symbolic date in Russia.

Li said the goal of the festivities would be, among other things, to "protect international justice and international order after the war."

China has spoken out against Western sanctions against Russia and has called on all sides to reach a political settlement over Ukraine.

- Currency swap line -

Among the top business deals was an agreement to open a currency swap line worth 150 billion yuan ($24.5 billion) to promote bilateral trade and investment.

"The agreement has been concluded for a period of three years and can be prolonged following agreement of the two sides," Russia's central bank said.

It allows the countries to use each other's currencies without buying them on the currency markets, said the bank.

Li's three-day Russia trip is part of a week-long visit to Europe.

Once bitter foes during the Cold War, Moscow and Beijing have over the past years ramped up cooperation as both are driven by a desire to counterbalance US global dominance.

China and Russia often work in lockstep at the UN Security Council, using their veto power as permanent council members to counter the West on issues such as the Syria crisis.

Russia's showdown with the West over Ukraine has given Moscow a new impetus to court Beijing.

Resource-hungry China is seeking to diversify its sources of energy amid booming domestic consumption, while Russia is seeking to tap fast-developing Asian markets.

After a decade of tough negotiations China and Russia inked a 30-year, $400-billion agreement in May that will eventually involve 38 billion cubic metres of gas annually.

Critics however disparaged the terms of the deal, saying Putin, in his bid to spite the West, signed an agreement that was more beneficial to China than to Russia.

Ahead of his Moscow visit, Li travelled to Germany for talks with Chancellor Angela Merkel. He will also participate in a summit in Milan later this week.