Aggressive US tactics such as a campaign against Chinese telecoms firm Huawei will lead to trade wars — and possibly real wars — Russian President Vladimir Putin has said, in a show of solidarity with China and its leader, Xi Jinping.

Key points: Both Russia's and China's relations have soured with the US under Donald Trump

Both Russia's and China's relations have soured with the US under Donald Trump Vladimir Putin has said US aggression could lead to trade and real wars

Vladimir Putin has said US aggression could lead to trade and real wars Xi Jinping referred to Putin as his "best friend" amid friendly meetings

In some of his strongest words to date on the subject, Mr Putin accused President Donald Trump's administration of "unbridled economic egoism".

He singled out US efforts to thwart a Russian gas pipeline to Europe and a US campaign to persuade countries to bar Huawei, the world's biggest telecoms equipment maker, from supplying network gear.

Mr Putin's comments represent a clear show of unity with China at a time when Beijing is locked in a trade war with Washington and Moscow's own ties with the West are at a post-Cold War low.

"States which previously promoted free trade with honest and open competition have started speaking the language of trade wars and sanctions, of open economic raiding using arm-twisting and scare tactics, of eliminating competitors," he said.

"Look for example at the situation around Huawei, which they are trying not to just squeeze out, but to unceremoniously push out of the global market."

"It's already being called the first technological war of the emerging digital era in some circles," Mr Putin said.

"It's a path to endless conflicts, trade wars and maybe not just trade wars. Figuratively speaking, it's a path to battles without rules that pit everyone against everyone else," he added.

Mr Xi struck a more conciliatory tone, calling for world powers to protect the global multilateral trade system.

Speaking through an interpreter, he said it was "hard to imagine a complete break" between the United States and China.

"We are not interested in this, and our American partners are not interested in this. President Trump is my friend and I am convinced he is also not interested in this," Mr Xi said.

Xi Jinping this week referred to Vladimir Putin as his best friend. ( AP: Alexei Druzhinin, Sputnik, Kremlin Pool Photo )

Closer ties between Russia and China

Relations between Russia and China have become increasingly close as they both face mounting tensions with the US.

Moscow's ties with Washington have declined sharply over the Ukrainian crisis, the war in Syria and the allegations of Kremlin meddling in the US 2016 presidential elections.

Mr Xi and Mr Putin met in Moscow and St Petersburg this week as world leaders gathered in England to mark the 75th anniversary of the D-Day landings.

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During a press conference, Mr Xi referred to Mr Putin as his "best friend" and noted that "in the past six years, we have met nearly 30 times."

"Russia is the country that I have visited the most times, and President Putin is my best friend and colleague," he said.

The Chinese leader said the two countries would coordinate their efforts in the energy sphere more closely.

Mr Putin also hailed the two countries' bilateral relations, saying that their cooperation in the global arena is "a major factor of stability in global affairs."

Russia has long complained about Western sanctions against Moscow, which it casts as an attempt to contain its growth.

Washington has asked countries to reject Huawei technology in the development of new mobile phone networks, arguing that it could be vulnerable to Chinese eavesdropping.

Huawei denies its equipment is a security risk.

Mr Trump said on Thursday that he'll make a decision about ramping up tariffs on China after he speaks with Mr Xi at a G20 summit in Japan this month.

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