President Joe Biden’s trip to Asia concluded with a bang as Russia and China sent him off with joint warplane exercises. According to a senior Biden administration official, Tuesday’s exercises were the first conducted by China and Russia since Moscow invaded Ukraine back in February. However earlier that month, the leaders of each country met to express their solidarity ahead of this year’s Winter Olympic Games in Beijing.

“We think it shows that China continues to be willing to closely align themselves with Russia, including through military cooperation,” the officials said. “China is not walking away from Russia. Instead, the exercise shows that China is ready to help Russia defend its east while Russia fights in its west.”

The joint warplane exercises from Russia and China were notable because they approached Japan’s airspace as the country was hosting a summit between leaders of the Quad. These leaders include:

• President Biden
• Japanese Prime Minister Fumio Kishida
• Indian Prime Minister Narendra Modi
• Australian Prime Minister Anthony Albanese

“We strongly support the principles of freedom, rule of law, democratic values, sovereignty and territorial integrity, peaceful settlement of disputes without resorting to threat or use of force, any unilateral attempt to change the status quo, and freedom of navigation and overflight, all of which are essential to the peace, stability and prosperity of the Indo-Pacific region and to the world,” the Quad leaders said in a joint statement Tuesday. “We reaffirm our resolve to uphold the international rules-based order where countries are free from all forms of military, economic and political coercion.”

Russia and China have been a frequent target of Biden’s during his Asia trip. On Monday, he said the United States military would intervene in the ongoing tensions between China and Taiwan should they escalate. While Biden refused to elaborate on those comments at the summit, China had more to say Tuesday.

“The U.S. has reneged on its commitment to the Taiwan issue, hollowed out the one-China principle, and explicitly and implicitly encouraged and supported the secessionist activities of Taiwan independence,” Chinese Foreign Ministry spokesperson Wang Wenbin said. “If it continues on the wrong path, it will not only cause irreparable consequences for U.S.-China relations, but will also eventually cost the U.S. an unbearable price.”

Russia and China weren’t the only topics of conversation during Biden’s trip. Other highlights include:

• A new trade deal with 12 Indo-Pacific nations
• A tour of a Samsung plant in South Korea
• Two Secret Service members being removed from South Korea for an alcohol-fueled incident before Biden arrived

Reuters contributed to this report.