(CNN) China and Russia are publicly heralding a new age of diplomacy between the two countries, at a time when both are being targeted by the United States with punitive measures.

During a visit to Moscow on Thursday, Chinese Foreign Minister Wang Yi was quoted as saying relations between two countries were at "the best level in history."

It comes as the United States has announced further sweeping trade actions targeted at China, revealing another $100 billion in possible tariffs on Thursday night.

Meanwhile Russia faces an ongoing, international diplomatic fallout following the poisoning of former Russian double agent in the United Kingdom, for which London blames the Kremlin.

"China's asserting the viability of an alternate world order, one which is separate to and stands up to America ... They've both got reason to push back against the United States," Richard McGregor, senior fellow at Sydney's Lowy Institute, told CNN.

Wang is wrapping up a visit to Moscow where the senior Chinese diplomat met with Russian President Vladimir Putin, who is planning to pay a state visit to Beijing in June.

During the same visit, China's new defense minister Gen. Wei Fenghe said Beijing was ready to join with Moscow to express "our common concerns and common position on important international problems."

"The Chinese side has come (to Moscow) to show Americans the close ties between the armed forces of China and Russia ... we've come to support you," he said.

McGregor said while the two countries had grown closer in the past decade, it was hard to tell exactly how deep the affection ran and how much was simply for show.

"That's always been the big question -- how much is this a partnership of convenience? To what extent are they putting down genuine roots, for two countries who haven't really liked each other," he said.

Russian President Vladimir Putin meets with Chinese Foreign Minister Wang Yi at the Kremlin in Moscow on April 5.

Complicated history

Russia and China were initially very close in the 1950s following the Communist Party taking power in Beijing, leading to a lot of cooperation between the two socialist powers.

"The Soviet Union supplied them with a lot of technical assistance -- people, money and technology," Peter Layton, Visiting Fellow at the Griffith Asia Institute, told CNN.

The two countries fell out severely over the following decades, to the extent Beijing was even nervous of a possible attack from their northern neighbors, Layton said.

In the past decade, relations have been largely restored, amid large sales of weapons and energy between the two countries.

According to McGregor, part of the rapprochement is due to a respect in Beijing for Putin, who Wang praised directly during recent visit. "We are fully confident about Russia's bright future under your leadership," Wang said, according to TASS.

"They have a lot of time for Putin," McGregor said. "They see him as someone who's restoring a strong government whereas (former Russian leader Mikhail Gorbachev) destroyed it."

China sides with Russia in UK poisoning

Amid an ongoing international diplomatic crisis around UK accusations Russia was behind the poisoning of a former double agent in the British town of Salisbury in March, Beijing has remained mostly silent.

Chinese Foreign Ministry spokesman Geng Shuang demurred when asked at his daily press conference on Tuesday about the attack.

"We know that the relevant parties have yet to reach a conclusion on the Skripal incident that all sides find acceptable," he said.

"China maintains that the relevant parties shall sort out the facts behind the Skripal incident at an early date and properly resolve disputes based on mutual respect and equal-footed consultation."

Beijing also hasn't joined other major nations around the world in expelling Russian diplomats in recent weeks, including the United States, Canada and Australia.

McGregor said it is just the latest in a series of close foreign policy coordination between Moscow and Beijing. The two countries have long supported each other at the United Nations.

"China never said much on Putin's take over of Crimea, they've worked closely on the North Korea crisis (and) China has not been critical of Russia's role in Syria," he said.