Russian President Vladimir Putin and Chinese leader Xi Jinping have common interests but very different diplomatic styles and goals, according to observations by Robert Daly, director of the Kissinger Institute on China and the United States, CNBC reported.

“China and Russia are probably closer now than at any time in the last 70 years,” Daly noted.

At a meeting between the two leaders in Beijing, China pledged to support Russia’s position on Ukraine’s NATO membership, but Xi Jinping believes it is not in his country’s interest to get involved in border tensions with Ukraine.

Daley made the comments days after Putin and Xi met on the opening day of the Winter Olympics and announced a “borderless” partnership between the two countries.

“Such a joint announcement could be a milestone in relations between Russia and China. It was very close to announcing a quasi-alliance,” Daly said, adding, “Both countries stand shoulder to shoulder to confront the United States, but China has a long-standing policy of non-alignment, so it doesn’t want to use the word ‘ally.'”

In geopolitics, however, the two countries do not fully harmonize their actions: Russia sells arms to Vietnam and India, which have had territorial disputes with China in recent years, and has not come out in favor of China’s actions in the South China Sea, which is commercially important to Vietnam, Japan and other countries, but much of which China claims as its territory.

For its part, China abstained from voting on a UN resolution following Russia’s annexation of Crimea in 2014 regarding its international status.

Beijing has pledged to support Moscow’s position to prevent Ukraine from joining NATO, but according to Daly, it is not in Beijing’s interest to get involved in military tensions on the border with Ukraine, as China has good relations with Ukraine and would prefer a military conflict not to happen.

In the event of an “invasion,” China would support Russia, but it would have to pay the price of facing a negative reaction from the United States and its allies, according to Bonnie Lin, director of the China Power Project at the Center for Strategic and International Studies.

Nevertheless, China’s relationship with Russia would not be cut off in the event of a conflict, she predicted. “Borderless partnership” between Russia and China opens the possibility of a formal military alliance, but both countries just need each other’s political and economic support.

China will find ways to support Russia if the U.S. imposes punitive sanctions against Moscow, for example, this could include cooperation between banks or buying more Russian goods.

For now, China doesn’t want to specifically consider or talk about anything until Russia makes a move, and until we see a response to it from the U.S. and other Western countries. In fact, China’s strongest partner is Russia.