Japan recently confirmed that two Chinese aircraft carriers have been operating together in the Pacific for the first time, raising concerns in Tokyo about Beijing's expanding military presence beyond its borders.

Aircraft carriers play a crucial role in power projection over long distances. While China has previously sent naval vessels and warplanes to the disputed East China Sea islands, this recent development marks a significant shift as the carriers ventured as far as the second-island chain, including Guam, a U.S. territory.

Here's a closer look at the latest actions by China, which boasts the world's largest navy in terms of numbers.

How the Carriers Operated

Japan's Defense Ministry confirmed that the Chinese carriers, Liaoning and Shandong, were observed operating near southern Pacific islands simultaneously for the first time. Both carriers were spotted near Iwo Jima, about 1,200 kilometers south of Tokyo. The Liaoning also sailed within Japan's exclusive economic zone off Minamitorishima, the country's easternmost island.

Warplanes from both carriers were launched and landed during the operations. Japan expressed concern after a Chinese fighter jet flew close to a Japanese reconnaissance aircraft, prompting Japan to request preventive measures from China to avoid accidental collisions.

Reasons for Japan's Concern

China's expanding military activities have heightened tensions in the region. By sailing beyond the first-island chain and reaching the second-island chain, China has demonstrated its ability to challenge not only Japan but also its ally, the United States. Japan has pledged to enhance its air defense capabilities in response to China's actions.

China's Growing Navy

China's navy confirmed that the recent deployments were part of routine training in the western Pacific to test capabilities in far seas protection and joint operations. The country is pursuing a significant military modernization program, including ambitions for a blue-water naval force capable of extended operations at long ranges.

While China has the largest navy in terms of numbers, it lags behind the United States in aircraft carriers. China currently has three carriers compared to the U.S.'s 11, giving the U.S. a numerical advantage in naval operations.

Chinese Carriers' Capabilities

The two Chinese carriers in the western Pacific use the older ski-jump launch method for aircraft, with the third carrier expected to employ a more modern electromagnetic-type launch system. China's carriers are conventionally powered, unlike the U.S. carriers, which are nuclear-powered, allowing for greater operational range and power.

Other Naval Actions by China

China's military activities near Japan have included airspace violations, territorial waters violations, and joint military operations with Russia. Tokyo remains vigilant about China's actions in the region, particularly around the disputed East China Sea islands.