Coordinated strategic Russian and Chinese bombers were spotted in the northeastern waters of East Asia in a show of force to President Biden, who was visiting the region.

The Russian and Chinese bombers flew over the Sea of Japan and the East China Sea to send off Biden, who was in Tokyo, to meet with the leaders of the Quad group of countries. The fly-by was part of a joint military exercise held by Russia and China, the first one the two partners had since the invasion of Ukraine, which started last February 24.

The US government was monitoring the military exercise as the President was meeting with the leaders of Japan, Australia, and India. The group, called the Quad coalition, was a partnership created to combat the growing Chinese influence in the Indo-Pacific.

According to a senior US official, the Russian and Chinese bombers initially flew over the Sea of Japan and then continued south to the Philippine Sea. South Korea, which was in the vicinity of the exercise, issued a statement confirming that two Chinese warplanes and four Russian aircraft entered the country’s air defense identification zone (ADIZ) off its east coast.

The US official also noted that evidence from American agencies reveals that Chinese naval ships also likely took part in the military exercise. Joint exercises that deploy strategic bombers are more complex and require more stringent planning to coordinate. The White House condemned the exercise shortly after it was confirmed.